diff --git a/app/Http/Kernel.php b/app/Http/Kernel.php
index 93bf68b..95714cf 100644
--- a/app/Http/Kernel.php
+++ b/app/Http/Kernel.php
@@ -35,6 +35,7 @@ class Kernel extends HttpKernel
             \Illuminate\View\Middleware\ShareErrorsFromSession::class,
             \App\Http\Middleware\VerifyCsrfToken::class,
             \Illuminate\Routing\Middleware\SubstituteBindings::class,
+            \App\Http\Middleware\NormalizeLineEnding::class,
         ],
 
         'api' => [
diff --git a/app/Http/Middleware/NormalizeLineEnding.php b/app/Http/Middleware/NormalizeLineEnding.php
new file mode 100644
index 0000000..e0ec87e
--- /dev/null
+++ b/app/Http/Middleware/NormalizeLineEnding.php
@@ -0,0 +1,30 @@
+<?php
+
+namespace App\Http\Middleware;
+
+use Closure;
+
+/**
+ * リクエスト内の改行コードを正規化する。
+ * @package App\Http\Middleware
+ */
+class NormalizeLineEnding
+{
+    /**
+     * Handle an incoming request.
+     *
+     * @param  \Illuminate\Http\Request  $request
+     * @param  \Closure  $next
+     * @return mixed
+     */
+    public function handle($request, Closure $next)
+    {
+        $newInput = [];
+        foreach ($request->input() as $key => $value) {
+            $newInput[$key] = str_replace(["\r\n", "\r"], "\n", $value);
+        }
+        $request->replace($newInput);
+
+        return $next($request);
+    }
+}