diff --git a/lib/message_event.rb b/lib/message_event.rb
index de2e7516e4a93308c924656bd6e6480748358a9a..bdf42aed831144dd0af791afc5abce3aef49ee4e 100644
--- a/lib/message_event.rb
+++ b/lib/message_event.rb
@@ -23,7 +23,7 @@ module MessageEvent
 		end
 
 		def self.match?(value)
-			value.to_s.match?(/\A(\+1)?\d+\Z/)
+			value.to_s.match?(/\A\+?\d+\Z/)
 		end
 	end