diff --git a/src/UniTask/Assets/Plugins/UniTask/Runtime/UniTaskObservableExtensions.cs b/src/UniTask/Assets/Plugins/UniTask/Runtime/UniTaskObservableExtensions.cs
index d54a5fdb..d2bd9614 100644
--- a/src/UniTask/Assets/Plugins/UniTask/Runtime/UniTaskObservableExtensions.cs
+++ b/src/UniTask/Assets/Plugins/UniTask/Runtime/UniTaskObservableExtensions.cs
@@ -133,7 +133,7 @@ static void OnCanceled(object state)
             {
                 var self = (ToUniTaskObserver<T>)state;
                 self.disposable.Dispose();
-                self.promise.TrySetCanceled();
+                self.promise.TrySetCanceled(self.cancellationToken);
             }
 
             public void OnNext(T value)
@@ -203,7 +203,7 @@ static void OnCanceled(object state)
             {
                 var self = (FirstValueToUniTaskObserver<T>)state;
                 self.disposable.Dispose();
-                self.promise.TrySetCanceled();
+                self.promise.TrySetCanceled(self.cancellationToken);
             }
 
             public void OnNext(T value)