diff --git a/lib/rgrb/plugin/url_fetch_title/generator.rb b/lib/rgrb/plugin/url_fetch_title/generator.rb
index b861ab69..32ec08ce 100644
--- a/lib/rgrb/plugin/url_fetch_title/generator.rb
+++ b/lib/rgrb/plugin/url_fetch_title/generator.rb
@@ -20,11 +20,11 @@ def initialize(*args)
         end
 
         def configure(config_data)
-          @no_ssl_verify = config_data['NoSSLVerify']
+          @no_ssl_verify = config_data['NoSSLVerify'] || []
           @agent.open_timeout = config_data['OpenTimeout']
           @agent.read_timeout = config_data['ReadTimeout']
-          @reply_prefix = config_data['ReplyPrefix']
-          @reply_suffix = config_data['ReplySuffix']
+          @reply_prefix = config_data['ReplyPrefix'] || 'Fetch title: '
+          @reply_suffix = config_data['ReplySuffix'] || ''
         end
 
         # 誰かが発言した URL にアクセスし、ページの title タグを取得する