diff --git a/dictation_server/src/features/users/types/types.ts b/dictation_server/src/features/users/types/types.ts
index 77ac6c8..4478c13 100644
--- a/dictation_server/src/features/users/types/types.ts
+++ b/dictation_server/src/features/users/types/types.ts
@@ -1,5 +1,5 @@
 import { ApiProperty } from '@nestjs/swagger';
-import { IsBoolean, IsEmail, IsIn, IsInt, MaxLength } from 'class-validator';
+import { IsBoolean, IsEmail, IsIn, IsInt, IsOptional, MaxLength } from 'class-validator';
 import {
   TASK_LIST_SORTABLE_ATTRIBUTES,
   USER_LICENSE_STATUS,
@@ -291,6 +291,7 @@ export class UpdateAcceptedVersionRequest {
   acceptedPrivacyNoticeVersion: string;
   @ApiProperty({ description: '更新バージョン（DPA）', required: false })
   @MaxLength(255)
+  @IsOptional()
   acceptedDPAVersion?: string;
 }