diff --git a/src/UniTask/Assets/Plugins/UniTask/Runtime/TimeoutController.cs b/src/UniTask/Assets/Plugins/UniTask/Runtime/TimeoutController.cs
index ad95cb5..63782a9 100644
--- a/src/UniTask/Assets/Plugins/UniTask/Runtime/TimeoutController.cs
+++ b/src/UniTask/Assets/Plugins/UniTask/Runtime/TimeoutController.cs
@@ -109,7 +109,7 @@ namespace Cysharp.Threading.Tasks
             try
             {
                 // stop timer.
-                timer.Dispose();
+                timer?.Dispose();
 
                 // cancel and dispose.
                 timeoutSource.Cancel();