diff --git a/digdag-docs/src/operators/s3_wait.md b/digdag-docs/src/operators/s3_wait.md
index 6a56318e15..a02d75ae27 100644
--- a/digdag-docs/src/operators/s3_wait.md
+++ b/digdag-docs/src/operators/s3_wait.md
@@ -102,7 +102,7 @@ For more information about SSE-C, See the [AWS S3 Documentation](http://docs.aws
     timeout: 60s
     continue_on_timeout: true
   +task2:
-    if>: ${s3.last_object}
+    if>: ${!!s3.last_object}
     _do:
       echo>: "No timeout"
   ```