diff --git a/worker.go b/worker.go
index 5b8426b..c4df148 100644
--- a/worker.go
+++ b/worker.go
@@ -55,7 +55,7 @@ func (w *Worker) run() {
 
 // stop this worker.
 func (w *Worker) stop() {
-	w.task <- nil
+	w.sendTask(nil)
 }
 
 // sendTask sends a task to this worker.
diff --git a/worker_func.go b/worker_func.go
index b8d59ec..b149411 100644
--- a/worker_func.go
+++ b/worker_func.go
@@ -55,7 +55,7 @@ func (w *WorkerWithFunc) run() {
 
 // stop this worker.
 func (w *WorkerWithFunc) stop() {
-	w.args <- nil
+	w.sendTask(nil)
 }
 
 // sendTask sends a task to this worker.