diff --git a/matrix_appservice_kakaotalk/portal.py b/matrix_appservice_kakaotalk/portal.py
index fcafc62..8fd5d59 100644
--- a/matrix_appservice_kakaotalk/portal.py
+++ b/matrix_appservice_kakaotalk/portal.py
@@ -487,7 +487,7 @@ class Portal(DBPortal, BasePortal):
             self.description = description
             if self.mxid and (self.encrypted or not self.is_direct):
                 try:
-                    await self.main_intent.set_room_topic(self.mxid, self.description)
+                    await self.main_intent.set_room_topic(self.mxid, self.description or "")
                     self.topic_set = True
                 except Exception:
                     self.log.exception("Failed to set room description")