diff --git a/.config/example.yml b/.config/example.yml
index a7145f498..01bf435c5 100644
--- a/.config/example.yml
+++ b/.config/example.yml
@@ -8,6 +8,9 @@ maintainer:
   feedback_url: https://github.com/syuilo/misskey/issues # Feedback URL (e.g. github issue)
 
 url: http://localhost/
+
+# A port that your Misskey server should listen.
+# This value is not a port to use when accessing with a browser.
 port: 80
 
 mongodb: