diff --git a/dictation_server/src/common/test/overrides.ts b/dictation_server/src/common/test/overrides.ts
new file mode 100644
index 0000000..054573e
--- /dev/null
+++ b/dictation_server/src/common/test/overrides.ts
@@ -0,0 +1,63 @@
+import { ConflictError } from '../../gateways/adb2c/adb2c.service';
+
+/**
+ * adB2cServiceのモックを作成して、TServiceが依存するサービス(adB2cService)の参照を上書きする
+ * ※ serviceに指定するオブジェクトは`adB2cService: AdB2cService`メンバ変数を持つ必要がある
+ * @param service 上書きしたいTService
+ * @param overrides adB2cServiceの各種メソッドのモックが返す値（省略した場合は既定のダミーの値）
+ */
+export const overrideAdB2cService = <TService>(
+  service: TService,
+  overrides: {
+    createUser?: (
+      email: string,
+      password: string,
+      username: string,
+    ) => Promise<{ sub: string } | ConflictError>;
+  },
+): void => {
+  const { createUser } = overrides;
+  Object.defineProperty(service, 'adB2cService', {
+    value: {
+      createUser: createUser ?? jest.fn().mockResolvedValue({ sub: 'dummy' }),
+    },
+  });
+};
+
+/**
+ * sendgridServiceのモックを作成して、TServiceが依存するサービス(sendgridService)の参照を上書きする
+ * ※ serviceに指定するオブジェクトは`sendgridService: SendgridService`メンバ変数を持つ必要がある
+ * @param service 上書きしたいTService
+ * @param overrides sendgridServiceの各種メソッドのモックが返す値（省略した場合は既定のダミーの値）
+ */
+export const overrideSendgridService = <TService>(
+  service: TService,
+  overrides: {
+    createMailContentFromEmailConfirm?: (
+      accountId: number,
+      userId: number,
+      email: string,
+    ) => Promise<{ subject: string; text: string; html: string }>;
+    sendMail?: (
+      to: string,
+      from: string,
+      subject: string,
+      text: string,
+      html: string,
+    ) => Promise<void>;
+  },
+): void => {
+  const { createMailContentFromEmailConfirm, sendMail } = overrides;
+  Object.defineProperty(service, 'sendgridService', {
+    value: {
+      createMailContentFromEmailConfirm:
+        createMailContentFromEmailConfirm ??
+        jest.fn().mockResolvedValue({
+          subject: 'dummySubject',
+          text: 'dummyText',
+          html: 'dummyHtml',
+        }),
+      sendMail: sendMail ?? jest.fn().mockResolvedValue(undefined),
+    },
+  });
+};
diff --git a/dictation_server/src/features/accounts/accounts.service.spec.ts b/dictation_server/src/features/accounts/accounts.service.spec.ts
index 4c523e8..f068766 100644
--- a/dictation_server/src/features/accounts/accounts.service.spec.ts
+++ b/dictation_server/src/features/accounts/accounts.service.spec.ts
@@ -16,6 +16,10 @@ import {
   createLicenseOrder,
   createUser,
   createLicenseSetExpiryDateAndStatus,
+  getAccount,
+  getUser,
+  getAccounts,
+  getUsers,
 } from './test/utility';
 import { DataSource } from 'typeorm';
 import { makeTestingModule } from '../../common/test/modules';
@@ -23,6 +27,176 @@ import { AccountsService } from './accounts.service';
 import { makeContext } from '../../common/log';
 import { TIERS } from '../../constants';
 import { License } from '../../repositories/licenses/entity/license.entity';
+import {
+  overrideAdB2cService,
+  overrideSendgridService,
+} from '../../common/test/overrides';
+
+describe('createAccount', () => {
+  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('アカウントを作成できる', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+
+    const externalId = 'test_external_id';
+    const companyName = 'test_company_name';
+    const country = 'US';
+    const dealerAccountId = 1;
+    const email = 'dummy@dummy.dummy';
+    const password = 'dummy_password';
+    const username = 'dummy_username';
+    const role = 'admin none';
+    const acceptedTermsVersion = '1.0.0';
+
+    overrideAdB2cService(service, {
+      createUser: async () => {
+        return { sub: externalId };
+      },
+    });
+    overrideSendgridService(service, {});
+
+    const { accountId, externalUserId, userId } = await service.createAccount(
+      companyName,
+      country,
+      dealerAccountId,
+      email,
+      password,
+      username,
+      role,
+      acceptedTermsVersion,
+    );
+    // 作成したアカウントのIDが返ってくるか確認
+    expect(accountId).toBe(1);
+    expect(externalUserId).toBe(externalId);
+    expect(userId).toBe(1);
+
+    // DB内が想定通りになっているか確認
+    const account = await getAccount(source, accountId);
+    const user = await getUser(source, externalUserId);
+    expect(account.company_name).toBe(companyName);
+    expect(account.country).toBe(country);
+    expect(account.parent_account_id).toBe(dealerAccountId);
+    expect(account.tier).toBe(TIERS.TIER5);
+    expect(account.primary_admin_user_id).toBe(user.id);
+    expect(account.secondary_admin_user_id).toBe(null);
+    expect(user.accepted_terms_version).toBe(acceptedTermsVersion);
+    expect(user.account_id).toBe(accountId);
+    expect(user.role).toBe(role);
+  });
+
+  it('アカウントを作成がAzure AD B2Cへの通信失敗によって失敗すると500エラーが発生する', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+
+    overrideAdB2cService(service, {
+      createUser: async () => {
+        throw new Error();
+      },
+    });
+
+    overrideSendgridService(service, {});
+
+    const companyName = 'test_company_name';
+    const country = 'US';
+    const dealerAccountId = 1;
+    const email = 'dummy@dummy.dummy';
+    const password = 'dummy_password';
+    const username = 'dummy_username';
+    const role = 'admin none';
+    const acceptedTermsVersion = '1.0.0';
+
+    try {
+      await service.createAccount(
+        companyName,
+        country,
+        dealerAccountId,
+        email,
+        password,
+        username,
+        role,
+        acceptedTermsVersion,
+      );
+    } catch (e) {
+      if (e instanceof HttpException) {
+        expect(e.getStatus()).toBe(HttpStatus.INTERNAL_SERVER_ERROR);
+        expect(e.getResponse()).toEqual(makeErrorResponse('E009999'));
+      } else {
+        expect(true).toBe(false); // ここには来てはいけない
+      }
+    }
+
+    // DB内が想定通りになっているか確認
+    const accounts = await getAccounts(source);
+    expect(accounts.length).toBe(0);
+    const users = await getUsers(source);
+    expect(users.length).toBe(0);
+  });
+
+  it('アカウントを作成がメールアドレス重複によって失敗すると400エラーが発生する', async () => {
+    const module = await makeTestingModule(source);
+    const service = module.get<AccountsService>(AccountsService);
+
+    overrideAdB2cService(service, {
+      createUser: async () => {
+        // EmailのConflictエラーを返す
+        return { reason: 'email', message: 'dummy' };
+      },
+    });
+
+    overrideSendgridService(service, {});
+
+    const companyName = 'test_company_name';
+    const country = 'US';
+    const dealerAccountId = 1;
+    const email = 'dummy@dummy.dummy';
+    const password = 'dummy_password';
+    const username = 'dummy_username';
+    const role = 'admin none';
+    const acceptedTermsVersion = '1.0.0';
+
+    try {
+      await service.createAccount(
+        companyName,
+        country,
+        dealerAccountId,
+        email,
+        password,
+        username,
+        role,
+        acceptedTermsVersion,
+      );
+    } catch (e) {
+      if (e instanceof HttpException) {
+        expect(e.getStatus()).toBe(HttpStatus.BAD_REQUEST);
+        expect(e.getResponse()).toEqual(makeErrorResponse('E010301'));
+      } else {
+        expect(true).toBe(false); // ここには来てはいけない
+      }
+    }
+
+    // DB内が想定通りになっているか確認
+    const accounts = await getAccounts(source);
+    expect(accounts.length).toBe(0);
+    const users = await getUsers(source);
+    expect(users.length).toBe(0);
+  });
+});
 
 describe('AccountsService', () => {
   it('アカウントに紐づくライセンス情報を取得する', async () => {
@@ -505,7 +679,7 @@ describe('getPartnerAccount', () => {
     );
 
     // 有効期限が14日後のライセンスを追加（5ライセンス）
-    let expiryDate = new Date();
+    const expiryDate = new Date();
     expiryDate.setDate(expiryDate.getDate() + 14);
     expiryDate.setHours(23, 59, 59, 999);
     for (let i = 0; i < 5; i++) {
diff --git a/dictation_server/src/features/accounts/accounts.service.ts b/dictation_server/src/features/accounts/accounts.service.ts
index 5d08225..bbe0e39 100644
--- a/dictation_server/src/features/accounts/accounts.service.ts
+++ b/dictation_server/src/features/accounts/accounts.service.ts
@@ -10,11 +10,7 @@ import {
 } from '../../gateways/adb2c/adb2c.service';
 import { Account } from '../../repositories/accounts/entity/account.entity';
 import { User } from '../../repositories/users/entity/user.entity';
-import {
-  LICENSE_EXPIRATION_THRESHOLD_DAYS,
-  TIERS,
-  USER_ROLES,
-} from '../../constants';
+import { TIERS, USER_ROLES } from '../../constants';
 import { makeErrorResponse } from '../../common/error/makeErrorResponse';
 import {
   TypistGroup,
diff --git a/dictation_server/src/features/accounts/test/utility.ts b/dictation_server/src/features/accounts/test/utility.ts
index 31f4237..e66bff0 100644
--- a/dictation_server/src/features/accounts/test/utility.ts
+++ b/dictation_server/src/features/accounts/test/utility.ts
@@ -30,6 +30,50 @@ export const createAccount = async (
   return { accountId: account.id };
 };
 
+/**
+ * テスト ユーティリティ: 指定IDのアカウントを取得する
+ * @param dataSource データソース
+ * @param id アカウントID
+ * @returns 該当アカウント
+ */
+export const getAccount = async (dataSource: DataSource, id: number) => {
+  return await dataSource.getRepository(Account).findOne({
+    where: { id: id },
+  });
+};
+
+/**
+ * テスト ユーティリティ: すべてのアカウントを取得する
+ * @param dataSource データソース
+ * @returns　該当アカウント一覧
+ */
+export const getAccounts = async (
+  dataSource: DataSource,
+): Promise<Account[]> => {
+  return await dataSource.getRepository(Account).find();
+};
+
+/**
+ * テスト ユーティリティ: 指定ExternalIdのアカウントを取得する
+ * @param dataSource データソース
+ * @param externalId 外部ID
+ * @returns 該当ユーザー
+ */
+export const getUser = async (dataSource: DataSource, externalId: string) => {
+  return await dataSource.getRepository(User).findOne({
+    where: { external_id: externalId },
+  });
+};
+
+/**
+ * テスト ユーティリティ: すべてのユーザーを取得する
+ * @param dataSource データソース
+ * @returns 該当ユーザー一覧
+ */
+export const getUsers = async (dataSource: DataSource): Promise<User[]> => {
+  return await dataSource.getRepository(User).find();
+};
+
 export const createLicense = async (
   datasource: DataSource,
   accountId: number,
diff --git a/dictation_server/src/repositories/accounts/entity/account.entity.ts b/dictation_server/src/repositories/accounts/entity/account.entity.ts
index 82d57ea..ad65437 100644
--- a/dictation_server/src/repositories/accounts/entity/account.entity.ts
+++ b/dictation_server/src/repositories/accounts/entity/account.entity.ts
@@ -22,16 +22,16 @@ export class Account {
   @Column()
   country: string;
 
-  @Column()
+  @Column({ default: false })
   delegation_permission: boolean;
 
-  @Column()
+  @Column({ default: false })
   locked: boolean;
 
   @Column()
   company_name: string;
 
-  @Column()
+  @Column({ default: false })
   verified: boolean;
 
   @Column({ nullable: true })
@@ -43,16 +43,16 @@ export class Account {
   @Column({ nullable: true })
   deleted_at?: Date;
 
-  @Column()
-  created_by: string;
+  @Column({ nullable: true })
+  created_by?: string;
 
-  @CreateDateColumn()
+  @CreateDateColumn({ default: () => "datetime('now', 'localtime')" }) // defaultはSQLite用設定値.本番用は別途migrationで設定
   created_at: Date;
 
-  @Column()
-  updated_by: string;
+  @Column({ nullable: true })
+  updated_by?: string;
 
-  @UpdateDateColumn()
+  @UpdateDateColumn({ default: () => "datetime('now', 'localtime')" }) // defaultはSQLite用設定値.本番用は別途migrationで設定
   updated_at: Date;
 
   @OneToMany(() => User, (user) => user.id)
diff --git a/dictation_server/src/repositories/users/entity/user.entity.ts b/dictation_server/src/repositories/users/entity/user.entity.ts
index 1e01643..7ed3f88 100644
--- a/dictation_server/src/repositories/users/entity/user.entity.ts
+++ b/dictation_server/src/repositories/users/entity/user.entity.ts
@@ -33,16 +33,16 @@ export class User {
   @Column({ nullable: true })
   accepted_terms_version?: string;
 
-  @Column()
+  @Column({ default: false })
   email_verified: boolean;
 
-  @Column()
+  @Column({ default: true })
   auto_renew: boolean;
 
-  @Column()
+  @Column({ default: true })
   license_alert: boolean;
 
-  @Column()
+  @Column({ default: true })
   notification: boolean;
 
   @Column({ nullable: true })
@@ -57,16 +57,16 @@ export class User {
   @Column({ nullable: true })
   deleted_at?: Date;
 
-  @Column()
+  @Column({ nullable: true })
   created_by: string;
 
-  @CreateDateColumn()
+  @CreateDateColumn({ default: () => "datetime('now', 'localtime')" }) // defaultはSQLite用設定値.本番用は別途migrationで設定
   created_at: Date;
 
-  @Column()
-  updated_by: string;
+  @Column({ nullable: true })
+  updated_by?: string;
 
-  @UpdateDateColumn()
+  @UpdateDateColumn({ default: () => "datetime('now', 'localtime')" }) // defaultはSQLite用設定値.本番用は別途migrationで設定
   updated_at: Date;
 
   @ManyToOne(() => Account, (account) => account.user)