diff --git a/packages/backend/test/e2e/endpoints.ts b/packages/backend/test/e2e/endpoints.ts
index 791a33e985..69a755c2a8 100644
--- a/packages/backend/test/e2e/endpoints.ts
+++ b/packages/backend/test/e2e/endpoints.ts
@@ -164,7 +164,7 @@ describe('Endpoints', () => {
 
 			assert.strictEqual(res.status, 200);
 			assert.strictEqual(typeof res.body === 'object' && !Array.isArray(res.body), true);
-			assert.strictEqual(res.body.id, alice.id);
+			assert.strictEqual((res.body as unknown as { id: string }).id, alice.id);
 		});
 
 		test('ユーザーが存在しなかったら怒る', async () => {
@@ -1064,7 +1064,7 @@ describe('Endpoints', () => {
 				userId: bob.id,
 			}, alice);
 			assert.strictEqual(res1.status, 204);
-			assert.strictEqual(res2.body?.memo, memo);
+			assert.strictEqual((res2.body as unknown as { memo: string })?.memo, memo);
 		});
 
 		test('自分に関するメモを更新できる', async () => {
@@ -1079,7 +1079,7 @@ describe('Endpoints', () => {
 				userId: alice.id,
 			}, alice);
 			assert.strictEqual(res1.status, 204);
-			assert.strictEqual(res2.body?.memo, memo);
+			assert.strictEqual((res2.body as unknown as { memo: string })?.memo, memo);
 		});
 
 		test('メモを削除できる', async () => {
@@ -1100,7 +1100,7 @@ describe('Endpoints', () => {
 			}, alice);
 
 			// memoには常に文字列かnullが入っている(5cac151)
-			assert.strictEqual(res.body.memo, null);
+			assert.strictEqual((res.body as unknown as { memo: string | null }).memo, null);
 		});
 
 		test('メモは個人ごとに独立して保存される', async () => {
@@ -1127,8 +1127,8 @@ describe('Endpoints', () => {
 				}, carol),
 			]);
 
-			assert.strictEqual(resAlice.body.memo, memoAliceToBob);
-			assert.strictEqual(resCarol.body.memo, memoCarolToBob);
+			assert.strictEqual((resAlice.body as unknown as { memo: string }).memo, memoAliceToBob);
+			assert.strictEqual((resCarol.body as unknown as { memo: string }).memo, memoCarolToBob);
 		});
 	});
 });