diff --git a/webapp/go/go.mod b/webapp/go/go.mod
index 77f2bc2c..0ea12403 100644
--- a/webapp/go/go.mod
+++ b/webapp/go/go.mod
@@ -2,8 +2,6 @@ module github.com/isucon/isucon9-qualify/webapp/go
 
 go 1.23
 
-toolchain go1.23.0
-
 require (
 	github.com/go-chi/chi/v5 v5.1.0
 	github.com/go-sql-driver/mysql v1.8.1