diff --git a/dictation_server/db/migrations/050-add-index-licenses_order.sql b/dictation_server/db/migrations/050-add-index-licenses_order.sql
new file mode 100644
index 0000000..006bde4
--- /dev/null
+++ b/dictation_server/db/migrations/050-add-index-licenses_order.sql
@@ -0,0 +1,7 @@
+-- +migrate Up
+ALTER TABLE `license_orders` ADD INDEX `idx_from_account_id_and_po_number` (from_account_id,po_number);
+ALTER TABLE `license_orders` DROP INDEX `license_orders_fk_from_account_id`;
+
+-- +migrate Down
+ALTER TABLE `license_orders` DROP INDEX `idx_from_account_id_and_po_number`;
+ALTER TABLE `license_orders` ADD INDEX `license_orders_fk_from_account_id` (from_account_id);
\ No newline at end of file
diff --git a/dictation_server/src/constants/index.ts b/dictation_server/src/constants/index.ts
index 439c7ed..4c63064 100644
--- a/dictation_server/src/constants/index.ts
+++ b/dictation_server/src/constants/index.ts
@@ -295,3 +295,16 @@ export const TERM_TYPE = {
  * @const {string}
  */
 export const USER_AUDIO_FORMAT = 'DS2(QP)';
+
+/**
+ * ユニットテスト実行をしている場合のNODE_ENVの値
+ * @const {string[]}
+ */
+export const NODE_ENV_TEST = 'test';
+
+/**
+ * SQLのlockOptionの種類
+ */
+export const DB_LOCK_MODE = {
+  PESSIMISTIC_WRITE: 'pessimistic_write',
+};
diff --git a/dictation_server/src/repositories/licenses/licenses.repository.service.ts b/dictation_server/src/repositories/licenses/licenses.repository.service.ts
index 988e8c1..2004be3 100644
--- a/dictation_server/src/repositories/licenses/licenses.repository.service.ts
+++ b/dictation_server/src/repositories/licenses/licenses.repository.service.ts
@@ -1,5 +1,5 @@
 import { Injectable, Logger } from '@nestjs/common';
-import { DataSource, EntityManager, In, Not } from 'typeorm';
+import { DataSource, In } from 'typeorm';
 import {
   LicenseOrder,
   License,
@@ -9,9 +9,11 @@ import {
 } from './entity/license.entity';
 import {
   CARD_LICENSE_LENGTH,
+  DB_LOCK_MODE,
   LICENSE_ALLOCATED_STATUS,
   LICENSE_ISSUE_STATUS,
   LICENSE_TYPE,
+  NODE_ENV_TEST,
   SWITCH_FROM_TYPE,
   TIERS,
 } from '../../constants';
@@ -415,15 +417,23 @@ export class LicensesRepositoryService {
       const licenseOrderRepo = entityManager.getRepository(LicenseOrder);
       const licenseRepo = entityManager.getRepository(License);
 
+      let lockOption = {};
+      // テスト環境の場合は悲観的ロックを行わない
+      if (process.env.NODE_ENV !== NODE_ENV_TEST) {
+        lockOption = { mode: DB_LOCK_MODE.PESSIMISTIC_WRITE };
+      }
+
       const issuingOrder = await licenseOrderRepo.findOne({
         where: {
           from_account_id: orderedAccountId,
           po_number: poNumber,
         },
         comment: `${context.getTrackingId()}_${new Date().toUTCString()}`,
+
+        ...lockOption,
       });
-      // 注文が存在しない場合、エラー
       if (!issuingOrder) {
+        // 注文が存在しない場合、エラー
         throw new OrderNotFoundError(`No order found for PONumber:${poNumber}`);
       }
       // 既に発行済みの注文の場合、エラー