diff --git a/dictation_server/src/api/odms/openapi.json b/dictation_server/src/api/odms/openapi.json
index 9931cf2..ff4098b 100644
--- a/dictation_server/src/api/odms/openapi.json
+++ b/dictation_server/src/api/odms/openapi.json
@@ -3263,7 +3263,7 @@
             "description": "セカンダリ管理者ID"
           }
         },
-        "required": ["delegationPermission"]
+        "required": ["delegationPermission", "primaryAdminUserId"]
       },
       "UpdateAccountInfoResponse": { "type": "object", "properties": {} },
       "ConfirmRequest": {
diff --git a/dictation_server/src/common/error/code.ts b/dictation_server/src/common/error/code.ts
index f6b6ff7..c639807 100644
--- a/dictation_server/src/common/error/code.ts
+++ b/dictation_server/src/common/error/code.ts
@@ -36,6 +36,7 @@ export const ErrorCodes = [
   'E010302', // authorId重複エラー
   'E010401', // PONumber重複エラー
   'E010501', // アカウント不在エラー
+  'E010502', // アカウント情報変更不可エラー
   'E010601', // タスク変更不可エラー（タスクが変更できる状態でない、またはタスクが存在しない）
   'E010602', // タスク変更権限不足エラー
   'E010603', // タスク不在エラー
diff --git a/dictation_server/src/common/error/message.ts b/dictation_server/src/common/error/message.ts
index 5ffdfec..484e9a4 100644
--- a/dictation_server/src/common/error/message.ts
+++ b/dictation_server/src/common/error/message.ts
@@ -25,6 +25,7 @@ export const errors: Errors = {
   E010302: 'This AuthorId already used Error',
   E010401: 'This PoNumber already used Error',
   E010501: 'Account not Found Error.',
+  E010502: 'Account information cannot be changed Error.',
   E010601: 'Task is not Editable Error',
   E010602: 'No task edit permissions Error',
   E010603: 'Task not found Error.',
diff --git a/dictation_server/src/features/accounts/accounts.controller.ts b/dictation_server/src/features/accounts/accounts.controller.ts
index 7d6bde3..bda8d6d 100644
--- a/dictation_server/src/features/accounts/accounts.controller.ts
+++ b/dictation_server/src/features/accounts/accounts.controller.ts
@@ -1002,18 +1002,18 @@ export class AccountsController {
       secondryAdminUserId,
     } = body;
     const token = retrieveAuthorizationToken(req);
-    const { userId } = jwt.decode(token, { json: true }) as AccessToken;
-
+    const { userId, tier } = jwt.decode(token, { json: true }) as AccessToken;
     const context = makeContext(userId);
-    // 仮。API実装で本実装
-    // await this.accountService.updateAccountInfo(
-    //   context,
-    //   userId,
-    //   parentAccountId,
-    //   delegationPermission,
-    //   primaryAdminUserId,
-    //   secondryAdminUserId,
-    // );
+
+    await this.accountService.updateAccountInfo(
+      context,
+      userId,
+      tier,
+      delegationPermission,
+      primaryAdminUserId,
+      parentAccountId,
+      secondryAdminUserId,
+    );
 
     return;
   }
diff --git a/dictation_server/src/features/accounts/accounts.service.spec.ts b/dictation_server/src/features/accounts/accounts.service.spec.ts
index 6f61cf0..6607a87 100644
--- a/dictation_server/src/features/accounts/accounts.service.spec.ts
+++ b/dictation_server/src/features/accounts/accounts.service.spec.ts
@@ -4974,6 +4974,179 @@ describe('パートナー一覧取得', () => {
   });
 });
 
+describe('アカウント情報更新', () => {
+  let source: DataSource = null;
+  beforeEach(async () => {
+    source = new DataSource({
+      type: 'sqlite',
+      database: ':memory:',
+      logging: false,
+      entities: [__dirname + '/../../**/*.entity{.ts,.js}'],
+      synchronize: true, // trueにすると自動的にmigrationが行われるため注意
+    });
+    return source.initialize();
+  });
+
+  afterEach(async () => {
+    await source.destroy();
+    source = null;
+  });
+  it('アカウント情報を更新する（第五階層が実行/セカンダリ管理者ユーザがnull）', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+    const { tier4Accounts: tier4Accounts } = await makeHierarchicalAccounts(
+      source,
+    );
+    const tier5Accounts = await makeTestAccount(source, {
+      parent_account_id: tier4Accounts[0].account.id,
+      tier: 5,
+    });
+    await service.updateAccountInfo(
+      makeContext('trackingId'),
+      tier5Accounts.admin.external_id,
+      tier5Accounts.account.tier,
+      true,
+      tier5Accounts.admin.id,
+      tier4Accounts[0].account.id,
+      undefined,
+    );
+
+    // DB内が想定通りになっているか確認
+    const account = await getAccount(source, tier5Accounts.account.id);
+    expect(account.parent_account_id).toBe(tier4Accounts[0].account.id);
+    expect(account.delegation_permission).toBe(true);
+    expect(account.primary_admin_user_id).toBe(tier5Accounts.admin.id);
+    expect(account.secondary_admin_user_id).toBe(null);
+  });
+  it('アカウント情報を更新する（第五階層以外が実行）', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+    const { tier3Accounts: tier3Accounts, tier4Accounts: tier4Accounts } =
+      await makeHierarchicalAccounts(source);
+    const adduser = await makeTestUser(source, {
+      account_id: tier4Accounts[0].account.id,
+      external_id: 'typist-user-external-id',
+      role: 'typist',
+    });
+    await service.updateAccountInfo(
+      makeContext('trackingId'),
+      tier4Accounts[0].users[0].external_id,
+      tier4Accounts[0].account.tier,
+      false,
+      tier4Accounts[0].users[0].id,
+      tier3Accounts[0].account.id,
+      adduser.id,
+    );
+
+    // DB内が想定通りになっているか確認
+    const account = await getAccount(source, tier4Accounts[0].account.id);
+    expect(account.parent_account_id).toBe(tier3Accounts[0].account.id);
+    expect(account.delegation_permission).toBe(false);
+    expect(account.primary_admin_user_id).toBe(tier4Accounts[0].users[0].id);
+    expect(account.secondary_admin_user_id).toBe(adduser.id);
+  });
+  it('アカウント情報を更新する（ディーラーアカウントが未入力）', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+    const { tier3Accounts: tier3Accounts, tier4Accounts: tier4Accounts } =
+      await makeHierarchicalAccounts(source);
+    const adduser = await makeTestUser(source, {
+      account_id: tier4Accounts[0].account.id,
+      external_id: 'typist-user-external-id',
+      role: 'typist',
+    });
+    await service.updateAccountInfo(
+      makeContext('trackingId'),
+      tier4Accounts[0].users[0].external_id,
+      tier4Accounts[0].account.tier,
+      false,
+      tier4Accounts[0].users[0].id,
+      undefined,
+      adduser.id,
+    );
+
+    // DB内が想定通りになっているか確認
+    const account = await getAccount(source, tier4Accounts[0].account.id);
+    expect(account.parent_account_id).toBe(null);
+    expect(account.delegation_permission).toBe(false);
+    expect(account.primary_admin_user_id).toBe(tier4Accounts[0].users[0].id);
+    expect(account.secondary_admin_user_id).toBe(adduser.id);
+  });
+  it('アカウント情報の更新に失敗する（ディーラー未存在）', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+    const { tier4Accounts: tier4Accounts } = await makeHierarchicalAccounts(
+      source,
+    );
+    const adduser = await makeTestUser(source, {
+      account_id: tier4Accounts[0].account.id,
+      external_id: 'typist-user-external-id',
+      role: 'typist',
+    });
+    await expect(
+      service.updateAccountInfo(
+        makeContext('trackingId'),
+        tier4Accounts[0].users[0].external_id,
+        tier4Accounts[0].account.tier,
+        false,
+        tier4Accounts[0].users[0].id,
+        123,
+        adduser.id,
+      ),
+    ).rejects.toEqual(
+      new HttpException(makeErrorResponse('E010502'), HttpStatus.BAD_REQUEST),
+    );
+  });
+  it('アカウント情報の更新に失敗する（プライマリ管理者ユーザ未存在）', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+    const { tier4Accounts: tier4Accounts } = await makeHierarchicalAccounts(
+      source,
+    );
+    const tier5Accounts = await makeTestAccount(source, {
+      parent_account_id: tier4Accounts[0].account.id,
+      tier: 5,
+    });
+    await expect(
+      service.updateAccountInfo(
+        makeContext('trackingId'),
+        tier5Accounts.admin.external_id,
+        tier5Accounts.account.tier,
+        true,
+        999,
+        tier4Accounts[0].account.id,
+        tier4Accounts[1].users[0].id,
+      ),
+    ).rejects.toEqual(
+      new HttpException(makeErrorResponse('E010502'), HttpStatus.BAD_REQUEST),
+    );
+  });
+  it('アカウント情報の更新に失敗する（セカンダリ管理者ユーザ未存在）', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+    const { tier4Accounts: tier4Accounts } = await makeHierarchicalAccounts(
+      source,
+    );
+    const tier5Accounts = await makeTestAccount(source, {
+      parent_account_id: tier4Accounts[0].account.id,
+      tier: 5,
+    });
+    await expect(
+      service.updateAccountInfo(
+        makeContext('trackingId'),
+        tier5Accounts.admin.external_id,
+        tier5Accounts.account.tier,
+        true,
+        tier4Accounts[0].users[0].id,
+        tier4Accounts[0].account.id,
+        999,
+      ),
+    ).rejects.toEqual(
+      new HttpException(makeErrorResponse('E010502'), HttpStatus.BAD_REQUEST),
+    );
+  });
+});
+
 describe('getAccountInfo', () => {
   let source: DataSource = null;
   beforeEach(async () => {
@@ -4991,7 +5164,6 @@ describe('getAccountInfo', () => {
     await source.destroy();
     source = null;
   });
-
   it('パラメータのユーザに対応するアカウント情報を取得できる', async () => {
     const module = await makeTestingModule(source);
     // 第五階層のアカウント作成
diff --git a/dictation_server/src/features/accounts/accounts.service.ts b/dictation_server/src/features/accounts/accounts.service.ts
index d2465c2..401bae4 100644
--- a/dictation_server/src/features/accounts/accounts.service.ts
+++ b/dictation_server/src/features/accounts/accounts.service.ts
@@ -37,12 +37,15 @@ import {
   ExpirationThresholdDate,
 } from '../licenses/types/types';
 import { GetLicenseSummaryResponse, Typist } from './types/types';
-import { AccessToken } from '../../common/token';
 import { UserNotFoundError } from '../../repositories/users/errors/types';
 import { UserGroupsRepositoryService } from '../../repositories/user_groups/user_groups.repository.service';
 import { makePassword } from '../../common/password';
 import { LicensesRepositoryService } from '../../repositories/licenses/licenses.repository.service';
-import { AccountNotFoundError } from '../../repositories/accounts/errors/types';
+import {
+  AccountNotFoundError,
+  AdminUserNotFoundError,
+  DealerAccountNotFoundError,
+} from '../../repositories/accounts/errors/types';
 import { Context } from '../../common/log';
 import {
   LicensesShortageError,
@@ -1605,4 +1608,72 @@ export class AccountsService {
       this.logger.log(`[OUT] [${context.trackingId}] ${this.getPartners.name}`);
     }
   }
+
+  /**
+   * アカウント情報を設定する
+   * @param context
+   * @param externalId
+   * @param tier
+   * @param delegationPermission
+   * @param primaryAdminUserId
+   * @param parentAccountId
+   * @param secondryAdminUserId
+   * @returns UpdateAccountInfoResponse
+   */
+  async updateAccountInfo(
+    context: Context,
+    externalId: string,
+    tier: number,
+    delegationPermission: boolean,
+    primaryAdminUserId: number,
+    parentAccountId?: number,
+    secondryAdminUserId?: number,
+  ): Promise<void> {
+    this.logger.log(
+      `[IN] [${context.trackingId}] ${this.updateAccountInfo.name} | params: { ` +
+        `externalId: ${externalId}, ` +
+        `delegationPermission: ${delegationPermission}, ` +
+        `primaryAdminUserId: ${primaryAdminUserId}, ` +
+        `parentAccountId: ${parentAccountId}, ` +
+        `secondryAdminUserId: ${secondryAdminUserId}, };`,
+    );
+
+    try {
+      const { account_id: accountId } =
+        await this.usersRepository.findUserByExternalId(externalId);
+      await this.accountRepository.updateAccountInfo(
+        accountId,
+        tier,
+        delegationPermission,
+        primaryAdminUserId,
+        parentAccountId,
+        secondryAdminUserId,
+      );
+    } catch (e) {
+      this.logger.error(`[${context.trackingId}] error=${e}`);
+      if (e instanceof Error) {
+        switch (e.constructor) {
+          case DealerAccountNotFoundError:
+          case AdminUserNotFoundError:
+            throw new HttpException(
+              makeErrorResponse('E010502'),
+              HttpStatus.BAD_REQUEST,
+            );
+          default:
+            throw new HttpException(
+              makeErrorResponse('E009999'),
+              HttpStatus.INTERNAL_SERVER_ERROR,
+            );
+        }
+      }
+      throw new HttpException(
+        makeErrorResponse('E009999'),
+        HttpStatus.INTERNAL_SERVER_ERROR,
+      );
+    } finally {
+      this.logger.log(
+        `[OUT] [${context.trackingId}] ${this.updateAccountInfo.name}`,
+      );
+    }
+  }
 }
diff --git a/dictation_server/src/features/accounts/types/types.ts b/dictation_server/src/features/accounts/types/types.ts
index 99672e3..f9675a0 100644
--- a/dictation_server/src/features/accounts/types/types.ts
+++ b/dictation_server/src/features/accounts/types/types.ts
@@ -547,9 +547,8 @@ export class UpdateAccountInfoRequest {
   parentAccountId?: number | undefined;
   @ApiProperty({ description: '代行操作許可' })
   delegationPermission: boolean;
-  @ApiProperty({ description: 'プライマリ管理者ID', required: false })
-  @IsOptional()
-  primaryAdminUserId?: number | undefined;
+  @ApiProperty({ description: 'プライマリ管理者ID' })
+  primaryAdminUserId: number;
   @ApiProperty({ description: 'セカンダリ管理者ID', required: false })
   @IsOptional()
   secondryAdminUserId?: number | undefined;
diff --git a/dictation_server/src/repositories/accounts/accounts.repository.service.ts b/dictation_server/src/repositories/accounts/accounts.repository.service.ts
index 6636f21..5da84e7 100644
--- a/dictation_server/src/repositories/accounts/accounts.repository.service.ts
+++ b/dictation_server/src/repositories/accounts/accounts.repository.service.ts
@@ -29,7 +29,11 @@ import {
   PartnerLicenseInfoForRepository,
   PartnerInfoFromDb,
 } from '../../features/accounts/types/types';
-import { AccountNotFoundError } from './errors/types';
+import {
+  AccountNotFoundError,
+  AdminUserNotFoundError,
+  DealerAccountNotFoundError,
+} from './errors/types';
 import {
   AlreadyLicenseAllocatedError,
   AlreadyLicenseStatusChangedError,
@@ -769,6 +773,103 @@ export class AccountsRepositoryService {
   }
 
   /**
+   * 一階層上のアカウントを取得する
+   * @param accountId
+   * @param tier
+   * @returns account: 一階層上のアカウント
+   */
+  async getOneUpperTierAccount(
+    accountId: number,
+    tier: number,
+  ): Promise<Account | undefined> {
+    return await this.dataSource.transaction(async (entityManager) => {
+      const accountRepo = entityManager.getRepository(Account);
+      return await accountRepo.findOne({
+        where: {
+          id: accountId,
+          tier: tier - 1,
+        },
+      });
+    });
+  }
+
+  /**
+   * アカウント情報を保存する
+   * @param myAccountId
+   * @param tier
+   * @param delegationPermission
+   * @param primaryAdminUserId
+   * @param parentAccountId
+   * @param secondryAdminUserId
+   */
+  async updateAccountInfo(
+    myAccountId: number,
+    tier: number,
+    delegationPermission: boolean,
+    primaryAdminUserId: number,
+    parentAccountId?: number,
+    secondryAdminUserId?: number,
+  ): Promise<void> {
+    await this.dataSource.transaction(async (entityManager) => {
+      // ディーラーアカウントが指定されている場合、存在チェックを行う
+      if (parentAccountId) {
+        const dealerAccount = await this.getOneUpperTierAccount(
+          parentAccountId,
+          tier,
+        );
+        // 取得できない場合、エラー
+        if (!dealerAccount) {
+          throw new DealerAccountNotFoundError(
+            `Dealer account is not found. id: ${parentAccountId}}`,
+          );
+        }
+      }
+
+      const userRepo = entityManager.getRepository(User);
+      // プライマリ管理者ユーザーの存在チェック
+      if (primaryAdminUserId) {
+        const primaryAdminUser = await userRepo.findOne({
+          where: {
+            id: primaryAdminUserId,
+            account_id: myAccountId,
+          },
+        });
+        if (!primaryAdminUser) {
+          throw new AdminUserNotFoundError(
+            `Primary admin user is not found. id: ${primaryAdminUserId}, account_id: ${myAccountId}`,
+          );
+        }
+      }
+
+      // セカンダリ管理者ユーザーの存在チェック
+      if (secondryAdminUserId) {
+        const secondryAdminUser = await userRepo.findOne({
+          where: {
+            id: secondryAdminUserId,
+            account_id: myAccountId,
+          },
+        });
+        if (!secondryAdminUser) {
+          throw new AdminUserNotFoundError(
+            `Secondry admin user is not found. id: ${secondryAdminUserId}, account_id: ${myAccountId}`,
+          );
+        }
+      }
+      const accountRepo = entityManager.getRepository(Account);
+      // アカウント情報を更新
+      await accountRepo.update(
+        { id: myAccountId },
+        {
+          parent_account_id: parentAccountId || null,
+          delegation_permission: delegationPermission,
+          primary_admin_user_id: primaryAdminUserId,
+          secondary_admin_user_id: secondryAdminUserId || null,
+        },
+      );
+    });
+  }
+
+  /*
    * ActiveWorktypeIdを更新する
    * @param accountId
    * @param [id] ActiveWorktypeIdの内部ID
diff --git a/dictation_server/src/repositories/accounts/errors/types.ts b/dictation_server/src/repositories/accounts/errors/types.ts
index 9b5145a..c273574 100644
--- a/dictation_server/src/repositories/accounts/errors/types.ts
+++ b/dictation_server/src/repositories/accounts/errors/types.ts
@@ -1,2 +1,6 @@
 // アカウント未発見エラー
 export class AccountNotFoundError extends Error {}
+// ディーラーアカウント未存在エラー
+export class DealerAccountNotFoundError extends Error {}
+// 管理者ユーザ未存在エラー
+export class AdminUserNotFoundError extends Error {}