diff --git a/__tests__/grpc/timetable.service.test.ts b/__tests__/grpc/timetable.service.test.ts
index 1e9ec09..f3b00ce 100644
--- a/__tests__/grpc/timetable.service.test.ts
+++ b/__tests__/grpc/timetable.service.test.ts
@@ -336,10 +336,11 @@ describe('deleteRegisteredCourse', () => {
   test('deleteRegisteredCourse', (done) => {
     const ids = [v4(), v4()]
     mocked(deleteRegisteredCoursesUseCase).mockImplementation(async (i) => {
-      expect(i).toEqual(deepContaining(ids))
+      expect(i.ids).toEqual(deepContaining(ids))
+      expect(i.userId).toEqual(userId)
     })
 
-    client.deleteRegisteredCourses({ ids }, (err, res) => {
+    client.deleteRegisteredCourses({ userId, ids }, (err, res) => {
       expect(err).toBeNull()
       done()
     })
@@ -351,7 +352,7 @@ describe('deleteRegisteredCourse', () => {
       throw new NotFoundError('指定された講義は見つかりませんでした')
     })
 
-    client.deleteRegisteredCourses({ ids }, (err, res) => {
+    client.deleteRegisteredCourses({ userId, ids }, (err, res) => {
       expect(err?.code).toBe(Status.NOT_FOUND)
       done()
     })
@@ -361,7 +362,7 @@ describe('deleteRegisteredCourse', () => {
     mocked(deleteRegisteredCoursesUseCase).mockImplementation(
       throwUnexpectedError
     )
-    client.deleteRegisteredCourses({ ids }, (err, res) => {
+    client.deleteRegisteredCourses({ userId, ids }, (err, res) => {
       expect(err?.code).toBeTruthy()
       done()
     })
@@ -372,10 +373,11 @@ describe('deleteTags', () => {
   test('deleteTags', (done) => {
     const ids = [v4(), v4()]
     mocked(deleteTagsUseCase).mockImplementation(async (i) => {
-      expect(i).toEqual(deepContaining(ids))
+      expect(i.ids).toEqual(deepContaining(ids))
+      expect(i.userId).toEqual(userId)
     })
 
-    client.deleteTags({ ids }, (err, res) => {
+    client.deleteTags({ userId, ids }, (err, res) => {
       expect(err).toBeNull()
       done()
     })
@@ -387,7 +389,7 @@ describe('deleteTags', () => {
       throw new NotFoundError('指定されたタグは見つかりませんでした')
     })
 
-    client.deleteTags({ ids }, (err, res) => {
+    client.deleteTags({ userId, ids }, (err, res) => {
       expect(err?.code).toBe(Status.NOT_FOUND)
       done()
     })
@@ -397,7 +399,7 @@ describe('deleteTags', () => {
     const ids = [v4(), v4()]
     mocked(deleteTagsUseCase).mockImplementation(throwUnexpectedError)
 
-    client.deleteTags({ ids }, (err, res) => {
+    client.deleteTags({ userId, ids }, (err, res) => {
       expect(err?.code).toBeTruthy()
       done()
     })
diff --git a/__tests__/usecase/deleteRegisteredCourses.test.ts b/__tests__/usecase/deleteRegisteredCourses.test.ts
index 81f52f6..a0ae8e0 100644
--- a/__tests__/usecase/deleteRegisteredCourses.test.ts
+++ b/__tests__/usecase/deleteRegisteredCourses.test.ts
@@ -60,14 +60,20 @@ beforeAll(async () => {
 
 test('既に存在するデータを正しく削除できる', () => {
   return expect(
-    deleteRegisteredCoursesUseCase(data.map((c) => c.id))
+    deleteRegisteredCoursesUseCase({ userId, ids: data.map((c) => c.id) })
   ).resolves.toBeUndefined()
 })
 
 test('存在しないデータはエラーになる', () => {
-  return expect(deleteRegisteredCoursesUseCase([v4()])).rejects.toThrow(
-    NotFoundError
-  )
+  return expect(
+    deleteRegisteredCoursesUseCase({ userId, ids: [v4()] })
+  ).rejects.toThrow(NotFoundError)
+})
+
+test('存在しないデータはエラーになる', () => {
+  return expect(
+    deleteRegisteredCoursesUseCase({ userId: v4(), ids: data.map((c) => c.id) })
+  ).rejects.toThrow(NotFoundError)
 })
 
 afterAll(disconnectDatabase)
diff --git a/__tests__/usecase/deleteTags.test.ts b/__tests__/usecase/deleteTags.test.ts
index dd8f697..c613016 100644
--- a/__tests__/usecase/deleteTags.test.ts
+++ b/__tests__/usecase/deleteTags.test.ts
@@ -23,12 +23,20 @@ beforeAll(async () => {
 
 test('正しく削除できる', () => {
   return expect(
-    deleteTagsUseCase(data.map((t) => t.id))
+    deleteTagsUseCase({ userId, ids: data.map((t) => t.id) })
   ).resolves.toBeUndefined()
 })
 
 test('存在しないデータでエラーになる', () => {
-  return expect(deleteTagsUseCase([v4()])).rejects.toThrow(NotFoundError)
+  return expect(deleteTagsUseCase({ userId, ids: [v4()] })).rejects.toThrow(
+    NotFoundError
+  )
+})
+
+test('存在しないデータでエラーになる', () => {
+  return expect(
+    deleteTagsUseCase({ userId: v4(), ids: data.map((t) => t.id) })
+  ).rejects.toThrow(NotFoundError)
 })
 
 afterAll(disconnectDatabase)
diff --git a/protos/TimetableService.proto b/protos/TimetableService.proto
index 1cfd51c..8694751 100644
--- a/protos/TimetableService.proto
+++ b/protos/TimetableService.proto
@@ -72,12 +72,14 @@ message UpdateTagsResponse {
 
 
 message DeleteRegisteredCoursesRequest {
-  repeated string ids = 1;
+  string userId = 1;
+  repeated string ids = 2;
 }
 message DeleteRegisteredCoursesResponse {}
 
 
 message DeleteTagsRequest {
-  repeated string ids = 1;
+  string userId = 1;
+  repeated string ids = 2;
 }
 message DeleteTagsResponse {}
\ No newline at end of file
diff --git a/src/grpc/timetable.service.ts b/src/grpc/timetable.service.ts
index 7da9ba9..f02b6bb 100644
--- a/src/grpc/timetable.service.ts
+++ b/src/grpc/timetable.service.ts
@@ -113,7 +113,7 @@ export const timetableService: GrpcServer<TimetableService> = {
   },
   async deleteRegisteredCourses({ request }, callback) {
     try {
-      await deleteRegisteredCoursesUseCase(request.ids)
+      await deleteRegisteredCoursesUseCase(request)
       callback(null, DeleteRegisteredCoursesResponse.create({}))
     } catch (e) {
       callback(toGrpcError(e))
@@ -121,7 +121,7 @@ export const timetableService: GrpcServer<TimetableService> = {
   },
   async deleteTags({ request }, callback) {
     try {
-      await deleteTagsUseCase(request.ids)
+      await deleteTagsUseCase(request)
       callback(null, DeleteTagsResponse.create({}))
     } catch (e) {
       callback(toGrpcError(e))
diff --git a/src/usecase/deleteRegisteredCourses.ts b/src/usecase/deleteRegisteredCourses.ts
index 4b6b3cf..341f115 100644
--- a/src/usecase/deleteRegisteredCourses.ts
+++ b/src/usecase/deleteRegisteredCourses.ts
@@ -2,11 +2,16 @@ import { getConnection } from 'typeorm'
 import { RegisteredCourse } from '../database/model/registeredCourse'
 import { NotFoundError } from '../error'
 
-type Input = string[]
+type Input = {
+  userId: string
+  ids: string[]
+}
 
-export async function deleteRegisteredCoursesUseCase(ids: Input) {
+export async function deleteRegisteredCoursesUseCase({ userId, ids }: Input) {
   const repository = getConnection().getRepository(RegisteredCourse)
-  const target = await repository.findByIds(ids)
+  const target = await repository.find({
+    where: ids.map((id) => ({ id, userId })),
+  })
   if (target.length !== ids.length)
     throw new NotFoundError(
       '指定された講義は見つかりませんでした',
diff --git a/src/usecase/deleteTags.ts b/src/usecase/deleteTags.ts
index 0d2674f..b68cc26 100644
--- a/src/usecase/deleteTags.ts
+++ b/src/usecase/deleteTags.ts
@@ -2,11 +2,16 @@ import { getConnection } from 'typeorm'
 import { Tag } from '../database/model/tag'
 import { NotFoundError } from '../error'
 
-type Input = string[]
+type Input = {
+  userId: string
+  ids: string[]
+}
 
-export async function deleteTagsUseCase(ids: Input) {
+export async function deleteTagsUseCase({ userId, ids }: Input) {
   const repository = getConnection().getRepository(Tag)
-  const target = await repository.findByIds(ids)
+  const target = await repository.find({
+    where: ids.map((id) => ({ id, userId })),
+  })
   if (target.length !== ids.length)
     throw new NotFoundError(
       '指定されたタグは見つかりませんでした',
diff --git a/src/usecase/updateRegisteredCourses.ts b/src/usecase/updateRegisteredCourses.ts
index 755e1ea..ff9959e 100644
--- a/src/usecase/updateRegisteredCourses.ts
+++ b/src/usecase/updateRegisteredCourses.ts
@@ -47,7 +47,9 @@ export async function updateRegisteredCourseUseCase(courses: Input[]) {
   })
   try {
     const repository = getConnection().getRepository(RegisteredCourse)
-    const target = await repository.findByIds(courses.map((c) => c.id))
+    const target = await repository.find({
+      where: courses.map(({ id, userId }) => ({ id, userId })),
+    })
     if (target.length !== courses.length)
       throw new NotFoundError(
         '指定された講義は見つかりませんでした',
diff --git a/src/usecase/updateTags.ts b/src/usecase/updateTags.ts
index ca05fc6..e96c39b 100644
--- a/src/usecase/updateTags.ts
+++ b/src/usecase/updateTags.ts
@@ -10,7 +10,9 @@ type Input = {
 
 export async function updateTagsUseCase(tags: Input[]) {
   const repository = getConnection().getRepository(Tag)
-  const target = await repository.findByIds(tags.map((t) => t.id))
+  const target = await repository.find({
+    where: tags.map(({ id, userId }) => ({ id, userId })),
+  })
   if (target.length !== tags.length)
     throw new NotFoundError(
       '指定されたタグが見つかりません',