diff --git a/src/test/java/org/fluentd/logger/TestFluentLogger.java b/src/test/java/org/fluentd/logger/TestFluentLogger.java
index b0c2d01..fd30112 100644
--- a/src/test/java/org/fluentd/logger/TestFluentLogger.java
+++ b/src/test/java/org/fluentd/logger/TestFluentLogger.java
@@ -442,7 +442,7 @@ public void run() {
                 }
             });
         }
-        Thread.sleep(1000);
+        Thread.sleep(4000);
         executorService.shutdown();
         executorService.awaitTermination(300, TimeUnit.SECONDS);