diff --git a/jsk_robot_common/jsk_robot_startup/scripts/smach_to_mail.py b/jsk_robot_common/jsk_robot_startup/scripts/smach_to_mail.py
index dee5af4b08..e892a383a1 100755
--- a/jsk_robot_common/jsk_robot_startup/scripts/smach_to_mail.py
+++ b/jsk_robot_common/jsk_robot_startup/scripts/smach_to_mail.py
@@ -182,7 +182,10 @@ def _send_mail(self, subject, state_list):
                 image = EmailBody()
                 image.type = 'img'
                 image.img_size = 100
-                image.img_data = x['IMAGE']
+                img_txt = x['IMAGE']
+                if isinstance(img_txt, bytes):
+                    img_txt = img_txt.decode('utf-8')
+                image.img_data = img_txt
                 email_msg.body.append(image)
                 email_msg.body.append(changeline)
         email_msg.body.append(changeline)