diff --git a/app/Http/Controllers/RegularContractCreateController.php b/app/Http/Controllers/RegularContractCreateController.php
index 95b71bf..f139897 100644
--- a/app/Http/Controllers/RegularContractCreateController.php
+++ b/app/Http/Controllers/RegularContractCreateController.php
@@ -98,7 +98,7 @@ class RegularContractCreateController extends Controller
         $parks_table = $query->skip(($page - 1) * $perPage)->take($perPage)->get();
 
         if ($sort === 'park_ruby' || $sort === 'station_name_ruby') {
-            setlocale(LC_COLLATE, 'ja_JP.UTF-8');
+            setlocale(LC_COLLATE, 'ja_JP.utf8');
             $parks_table = $parks_table->sort(function ($a, $b) use ($order, $sort) {
                 // null対策
                 $a_val = $a->$sort ?? '';