diff --git a/README.rst b/README.rst
index 0424e4e..19e6bc1 100644
--- a/README.rst
+++ b/README.rst
@@ -73,4 +73,4 @@ Special thanks to @ikawaha, @takuyaa, @nakagami and @janome_oekaki.
 Copyright
 ==========
 
-Copyright(C) 2022, Tomoko Uchida. All rights reserved.
+Copyright(C) 2015-2023, Tomoko Uchida. All rights reserved.