diff --git a/backend/config/app.php b/backend/config/app.php
index 1c269602..a86a4dc9 100644
--- a/backend/config/app.php
+++ b/backend/config/app.php
@@ -67,7 +67,7 @@ return [
     |
     */
 
-    'timezone' => 'UTC',
+    'timezone' => 'Tokyo/Asia',
 
     /*
     |--------------------------------------------------------------------------
@@ -80,7 +80,7 @@ return [
     |
     */
 
-    'locale' => 'en',
+    'locale' => 'ja',
 
     /*
     |--------------------------------------------------------------------------
diff --git a/backend/resources/lang/ja/validation.php b/backend/resources/lang/ja/validation.php
new file mode 100644
index 00000000..417d824a
--- /dev/null
+++ b/backend/resources/lang/ja/validation.php
@@ -0,0 +1,155 @@
+<?php
+
+return [
+
+    /*
+    |--------------------------------------------------------------------------
+    | Validation Language Lines
+    |--------------------------------------------------------------------------
+    |
+    | The following language lines contain the default error messages used by
+    | the validator class. Some of these rules have multiple versions such
+    | as the size rules. Feel free to tweak each of these messages here.
+    |
+    */
+
+    'accepted' => 'The :attribute must be accepted.',
+    'active_url' => 'The :attribute is not a valid URL.',
+    'after' => 'The :attribute must be a date after :date.',
+    'after_or_equal' => 'The :attribute must be a date after or equal to :date.',
+    'alpha' => ' :attribute は英文字のみです。',
+    'alpha_dash' => ' :attribute は英数字、ハイフン（-）、又はアンダーバー（_）のみです。',
+    'alpha_num' => ' :attribute は英数字のみです。',
+    'array' => ' :attribute はarrayです。',
+    'before' => 'The :attribute must be a date before :date.',
+    'before_or_equal' => 'The :attribute must be a date before or equal to :date.',
+    'between' => [
+        'numeric' => 'The :attribute must be between :min and :max.',
+        'file' => 'The :attribute must be between :min and :max kilobytes.',
+        'string' => 'The :attribute must be between :min and :max characters.',
+        'array' => 'The :attribute must have between :min and :max items.',
+    ],
+    'boolean' => 'The :attribute field must be true or false.',
+    'confirmed' => ' :attribute と確認用パスワードが異なります。',
+    'date' => ' :attribute 日付のみです。',
+    'date_equals' => 'The :attribute must be a date equal to :date.',
+    'date_format' => 'The :attribute does not match the format :format.',
+    'different' => 'The :attribute and :other must be different.',
+    'digits' => 'The :attribute must be :digits digits.',
+    'digits_between' => 'The :attribute must be between :min and :max digits.',
+    'dimensions' => 'The :attribute has invalid image dimensions.',
+    'distinct' => 'The :attribute field has a duplicate value.',
+    'email' => '正しいメールアドレスを入力してください。',
+    'ends_with' => 'The :attribute must end with one of the following: :values.',
+    'exists' => 'The selected :attribute is invalid.',
+    'file' => 'The :attribute must be a file.',
+    'filled' => 'The :attribute field must have a value.',
+    'gt' => [
+        'numeric' => 'The :attribute must be greater than :value.',
+        'file' => 'The :attribute must be greater than :value kilobytes.',
+        'string' => 'The :attribute must be greater than :value characters.',
+        'array' => 'The :attribute must have more than :value items.',
+    ],
+    'gte' => [
+        'numeric' => 'The :attribute must be greater than or equal :value.',
+        'file' => 'The :attribute must be greater than or equal :value kilobytes.',
+        'string' => 'The :attribute must be greater than or equal :value characters.',
+        'array' => 'The :attribute must have :value items or more.',
+    ],
+    'image' => 'The :attribute must be an image.',
+    'in' => 'The selected :attribute is invalid.',
+    'in_array' => 'The :attribute field does not exist in :other.',
+    'integer' => 'The :attribute must be an integer.',
+    'ip' => 'The :attribute must be a valid IP address.',
+    'ipv4' => 'The :attribute must be a valid IPv4 address.',
+    'ipv6' => 'The :attribute must be a valid IPv6 address.',
+    'json' => 'The :attribute must be a valid JSON string.',
+    'lt' => [
+        'numeric' => 'The :attribute must be less than :value.',
+        'file' => 'The :attribute must be less than :value kilobytes.',
+        'string' => 'The :attribute must be less than :value characters.',
+        'array' => 'The :attribute must have less than :value items.',
+    ],
+    'lte' => [
+        'numeric' => 'The :attribute must be less than or equal :value.',
+        'file' => 'The :attribute must be less than or equal :value kilobytes.',
+        'string' => 'The :attribute must be less than or equal :value characters.',
+        'array' => 'The :attribute must not have more than :value items.',
+    ],
+    'max' => [
+        'numeric' => 'The :attribute must not be greater than :max.',
+        'file' => 'プロフィール画像は最大1M以内です。',
+        'string' => '本文は最大 :attribute 文字以内です。',
+        'array' => 'The :attribute must not have more than :max items.',
+    ],
+    'mimes' => 'ファイル形式は :values のみです。',
+    'mimetypes' => 'The :attribute must be a file of type: :values.',
+    'min' => [
+        'numeric' => 'The :attribute must be at least :min.',
+        'file' => 'The :attribute must be at least :min kilobytes.',
+        'string' => 'The :attribute must be at least :min characters.',
+        'array' => 'The :attribute must have at least :min items.',
+    ],
+    'multiple_of' => 'The :attribute must be a multiple of :value.',
+    'not_in' => 'The selected :attribute is invalid.',
+    'not_regex' => 'The :attribute format is invalid.',
+    'numeric' => ' :attribute は半角数字のみです。',
+    'password' => 'パスワードは異なります。',
+    'present' => 'The :attribute field must be present.',
+    'regex' => 'The :attribute format is invalid.',
+    'required' => ' :attribute は必須です。',
+    'required_if' => 'The :attribute field is required when :other is :value.',
+    'required_unless' => 'The :attribute field is required unless :other is in :values.',
+    'required_with' => 'The :attribute field is required when :values is present.',
+    'required_with_all' => 'The :attribute field is required when :values are present.',
+    'required_without' => 'The :attribute field is required when :values is not present.',
+    'required_without_all' => 'The :attribute field is required when none of :values are present.',
+    'prohibited' => 'The :attribute field is prohibited.',
+    'prohibited_if' => 'The :attribute field is prohibited when :other is :value.',
+    'prohibited_unless' => 'The :attribute field is prohibited unless :other is in :values.',
+    'same' => 'The :attribute and :other must match.',
+    'size' => [
+        'numeric' => ' :attribute は :size 数字です。',
+        'file' => 'The :attribute must be :size kilobytes.',
+        'string' => ' :attribute は :size 文字です。',
+        'array' => ' :size 枚以上登録できません。',
+    ],
+    'starts_with' => 'The :attribute must start with one of the following: :values.',
+    'string' => 'The :attribute must be a string.',
+    'timezone' => 'The :attribute must be a valid zone.',
+    'unique' => '同じ :attribute は使用できません。',
+    'uploaded' => 'The :attribute failed to upload.',
+    'url' => 'The :attribute format is invalid.',
+    'uuid' => 'The :attribute must be a valid UUID.',
+
+    /*
+    |--------------------------------------------------------------------------
+    | Custom Validation Language Lines
+    |--------------------------------------------------------------------------
+    |
+    | Here you may specify custom validation messages for attributes using the
+    | convention "attribute.rule" to name the lines. This makes it quick to
+    | specify a specific custom language line for a given attribute rule.
+    |
+    */
+
+    'custom' => [
+        'attribute-name' => [
+            'rule-name' => 'custom-message',
+        ],
+    ],
+
+    /*
+    |--------------------------------------------------------------------------
+    | Custom Validation Attributes
+    |--------------------------------------------------------------------------
+    |
+    | The following language lines are used to swap our attribute placeholder
+    | with something more reader friendly such as "E-Mail Address" instead
+    | of "email". This simply helps us make our message more expressive.
+    |
+    */
+
+    'attributes' => [],
+
+];