diff --git a/app/models/artist_url.rb b/app/models/artist_url.rb
index 721da7bcc..531000d4f 100644
--- a/app/models/artist_url.rb
+++ b/app/models/artist_url.rb
@@ -9,6 +9,7 @@ class ArtistUrl < ActiveRecord::Base
     if url.nil?
       nil
     else
+      url = url.downcase
       url = url.gsub(/^https:\/\//, "http://")
       url = url.gsub(/^http:\/\/blog\d+\.fc2/, "http://blog.fc2")
       url = url.gsub(/^http:\/\/blog-imgs-\d+\.fc2/, "http://blog.fc2")