diff --git a/upstart/stud.conf b/upstart/stud.conf
index 4f26ec4..d38e14f 100644
--- a/upstart/stud.conf
+++ b/upstart/stud.conf
@@ -7,4 +7,10 @@ start on runlevel [23]
 respawn
 respawn limit unlimited
 
-exec stud --config /etc/stud/stud.cfg
+script
+  # If this job is failed, upstart supervisor will run again soon. It's too fast.
+  # Therefore a proper sleep is needed.
+  sleep ${SLEEP_SEC:-1}
+
+  exec stud --config /etc/stud/stud.cfg
+end script