diff --git a/dictation_server/src/features/accounts/accounts.controller.spec.ts b/dictation_server/src/features/accounts/accounts.controller.spec.ts
index b2bbf73..2761b0e 100644
--- a/dictation_server/src/features/accounts/accounts.controller.spec.ts
+++ b/dictation_server/src/features/accounts/accounts.controller.spec.ts
@@ -2,10 +2,12 @@ import { Test, TestingModule } from '@nestjs/testing';
 import { AccountsController } from './accounts.controller';
 import { AccountsService } from './accounts.service';
 import { ConfigModule } from '@nestjs/config';
+import { AuthService } from '../auth/auth.service';
 
 describe('AccountsController', () => {
   let controller: AccountsController;
   const mockAccountService = {};
+  const mockAuthService = {};
 
   beforeEach(async () => {
     const module: TestingModule = await Test.createTestingModule({
@@ -16,10 +18,12 @@ describe('AccountsController', () => {
         }),
       ],
       controllers: [AccountsController],
-      providers: [AccountsService],
+      providers: [AccountsService, AuthService],
     })
       .overrideProvider(AccountsService)
       .useValue(mockAccountService)
+      .overrideProvider(AuthService)
+      .useValue(mockAuthService)
       .compile();
 
     controller = module.get<AccountsController>(AccountsController);
diff --git a/dictation_server/src/features/accounts/accounts.controller.ts b/dictation_server/src/features/accounts/accounts.controller.ts
index 92206af..bb98487 100644
--- a/dictation_server/src/features/accounts/accounts.controller.ts
+++ b/dictation_server/src/features/accounts/accounts.controller.ts
@@ -8,6 +8,7 @@ import {
   UseGuards,
   Param,
   Query,
+  HttpException,
 } from '@nestjs/common';
 import {
   ApiOperation,
@@ -74,12 +75,15 @@ import { AccessToken } from '../../common/token';
 import jwt from 'jsonwebtoken';
 import { makeContext } from '../../common/log';
 import { v4 as uuidv4 } from 'uuid';
+import { AuthService } from '../auth/auth.service';
+import { makeErrorResponse } from '../../common/error/makeErrorResponse';
 
 @ApiTags('accounts')
 @Controller('accounts')
 export class AccountsController {
   constructor(
     private readonly accountService: AccountsService, //private readonly cryptoService: CryptoService,
+    private readonly authService: AuthService,
   ) {}
 
   @Post()
@@ -1116,11 +1120,22 @@ export class AccountsController {
   async getAccountInfoMinimalAccess(
     @Body() body: GetAccountInfoMinimalAccessRequest,
   ): Promise<GetAccountInfoMinimalAccessResponse> {
-    const context = makeContext(uuidv4());
+    // IDトークンの検証
+    const idToken = await this.authService.getVerifiedIdToken(body.idToken);
+    const isVerified = await this.authService.isVerifiedUser(idToken);
+    if (!isVerified) {
+      throw new HttpException(
+        makeErrorResponse('E010201'),
+        HttpStatus.BAD_REQUEST,
+      );
+    }
 
-    // TODO 仮実装。API実装タスクで本実装する。
-    // const idToken = await this.authService.getVerifiedIdToken(body.idToken);
-    // await this.accountService.getAccountInfoMinimalAccess(context, idToken);
-    return;
+    const context = makeContext(idToken.sub);
+
+    const tier = await this.accountService.getAccountInfoMinimalAccess(
+      context,
+      idToken.sub,
+    );
+    return { tier };
   }
 }
diff --git a/dictation_server/src/features/accounts/accounts.module.ts b/dictation_server/src/features/accounts/accounts.module.ts
index 4b43415..23cf65e 100644
--- a/dictation_server/src/features/accounts/accounts.module.ts
+++ b/dictation_server/src/features/accounts/accounts.module.ts
@@ -9,6 +9,7 @@ import { AdB2cModule } from '../../gateways/adb2c/adb2c.module';
 import { UserGroupsRepositoryModule } from '../../repositories/user_groups/user_groups.repository.module';
 import { BlobstorageModule } from '../../gateways/blobstorage/blobstorage.module';
 import { WorktypesRepositoryModule } from '../../repositories/worktypes/worktypes.repository.module';
+import { AuthService } from '../auth/auth.service';
 
 @Module({
   imports: [
@@ -22,6 +23,6 @@ import { WorktypesRepositoryModule } from '../../repositories/worktypes/worktype
     BlobstorageModule,
   ],
   controllers: [AccountsController],
-  providers: [AccountsService],
+  providers: [AccountsService, AuthService],
 })
 export class AccountsModule {}
diff --git a/dictation_server/src/features/accounts/accounts.service.spec.ts b/dictation_server/src/features/accounts/accounts.service.spec.ts
index c7786d5..e5ec12d 100644
--- a/dictation_server/src/features/accounts/accounts.service.spec.ts
+++ b/dictation_server/src/features/accounts/accounts.service.spec.ts
@@ -5595,3 +5595,127 @@ describe('deleteAccountAndData', () => {
     expect(userRecord).toBe(null);
   });
 });
+describe('getAccountInfoMinimalAccess', () => {
+  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('IDトークンのsub情報からアカウントの階層情報を取得できること(第五階層)', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+    // 第五階層のアカウント作成
+    const { account, admin } = await makeTestAccount(source, {
+      tier: 5,
+    });
+    const context = makeContext(admin.external_id);
+
+    // 作成したデータを確認
+    {
+      const tier5Account = await getAccount(source, account.id);
+      expect(tier5Account.tier).toBe(5);
+    }
+
+    const tier = await service.getAccountInfoMinimalAccess(
+      context,
+      admin.external_id,
+    );
+
+    //実行結果を確認
+    expect(tier).toBe(5);
+  });
+  it('IDトークンのSub情報からアカウントの階層情報を取得できること（第四階層）', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+    // 第四階層のアカウント作成
+    const { account, admin } = await makeTestAccount(source, {
+      tier: 4,
+    });
+    const context = makeContext(admin.external_id);
+
+    // 作成したデータを確認
+    {
+      const tier5Account = await getAccount(source, account.id);
+      expect(tier5Account.tier).toBe(4);
+    }
+
+    const tier = await service.getAccountInfoMinimalAccess(
+      context,
+      admin.external_id,
+    );
+
+    //実行結果を確認
+    expect(tier).toBe(4);
+  });
+  it('対象のユーザーが存在しない場合、400エラーとなること', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+    // 第四階層のアカウント作成
+    const { account, admin } = await makeTestAccount(source, {
+      tier: 4,
+    });
+    const context = makeContext(admin.external_id);
+
+    // 作成したデータを確認
+    {
+      const tier5Account = await getAccount(source, account.id);
+      expect(tier5Account.tier).toBe(4);
+    }
+
+    try {
+      await service.getAccountInfoMinimalAccess(context, 'fail_external_id');
+    } catch (e) {
+      if (e instanceof HttpException) {
+        expect(e.getStatus()).toEqual(HttpStatus.BAD_REQUEST);
+        expect(e.getResponse()).toEqual(makeErrorResponse('E010204'));
+      } else {
+        fail();
+      }
+    }
+  });
+  it('DBアクセスに失敗した場合、500エラーとなること', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+    // 第四階層のアカウント作成
+    const { account, admin } = await makeTestAccount(source, {
+      tier: 4,
+    });
+    const context = makeContext(admin.external_id);
+
+    // 作成したデータを確認
+    {
+      const tier5Account = await getAccount(source, account.id);
+      expect(tier5Account.tier).toBe(4);
+    }
+
+    //DBアクセスに失敗するようにする
+    const usersRepositoryService = module.get<UsersRepositoryService>(
+      UsersRepositoryService,
+    );
+    usersRepositoryService.findUserByExternalId = jest
+      .fn()
+      .mockRejectedValue('DB failed');
+
+    try {
+      await service.getAccountInfoMinimalAccess(context, admin.external_id);
+    } catch (e) {
+      if (e instanceof HttpException) {
+        expect(e.getStatus()).toEqual(HttpStatus.INTERNAL_SERVER_ERROR);
+        expect(e.getResponse()).toEqual(makeErrorResponse('E009999'));
+      } else {
+        fail();
+      }
+    }
+  });
+});
diff --git a/dictation_server/src/features/accounts/accounts.service.ts b/dictation_server/src/features/accounts/accounts.service.ts
index 0587575..c2dacad 100644
--- a/dictation_server/src/features/accounts/accounts.service.ts
+++ b/dictation_server/src/features/accounts/accounts.service.ts
@@ -1843,4 +1843,61 @@ export class AccountsService {
       `[OUT] [${context.trackingId}] ${this.deleteAccountAndData.name}`,
     );
   }
+
+  /**
+   * IDトークンのsubからアカウントの階層情報を取得します
+   * @param context
+   * @param externalId
+   * @returns account info minimal access
+   */
+  async getAccountInfoMinimalAccess(
+    context: Context,
+    externalId: string,
+  ): Promise<number> {
+    this.logger.log(
+      `[IN] [${context.trackingId}] ${this.getAccountInfoMinimalAccess.name} | params: { externalId: ${externalId} };`,
+    );
+
+    try {
+      const { account } = await this.usersRepository.findUserByExternalId(
+        externalId,
+      );
+      if (!account) {
+        throw new AccountNotFoundError(
+          `Account not found. externalId: ${externalId}`,
+        );
+      }
+
+      return account.tier;
+    } catch (e) {
+      this.logger.error(`[${context.trackingId}] error=${e}`);
+      if (e instanceof Error) {
+        switch (e.constructor) {
+          case UserNotFoundError:
+            throw new HttpException(
+              makeErrorResponse('E010204'),
+              HttpStatus.BAD_REQUEST,
+            );
+          case AccountNotFoundError:
+            throw new HttpException(
+              makeErrorResponse('E010501'),
+              HttpStatus.BAD_REQUEST,
+            );
+          default:
+            throw new HttpException(
+              makeErrorResponse('E009999'),
+              HttpStatus.INTERNAL_SERVER_ERROR,
+            );
+        }
+      }
+      throw new HttpException(
+        makeErrorResponse('E009999'),
+        HttpStatus.INTERNAL_SERVER_ERROR,
+      );
+    } finally {
+      this.logger.log(
+        `[OUT] [${context.trackingId}] ${this.getAccountInfoMinimalAccess.name}`,
+      );
+    }
+  }
 }