diff --git a/class/mtee-ogp-setting.php b/class/mtee-ogp-setting.php
new file mode 100644
index 0000000..bcd5c3f
--- /dev/null
+++ b/class/mtee-ogp-setting.php
@@ -0,0 +1,52 @@
+<?php
+if (!defined('ABSPATH')) {
+    exit;
+} // Exit if accessed directly
+
+if (!class_exists('mtee_ogp_setting')) {
+
+    class mtee_ogp_setting {
+
+
+        public function __construct() {
+
+            //Posts
+            //add_action('admin_menu', array($this, 'add_meta_fields'));
+        }
+
+        //-------------------------------------------------------------------------------------------
+        // 投稿、ページのカスタムフィールド設定
+        //-------------------------------------------------------------------------------------------
+        public function add_meta_fields() {
+            //add_meta_box(表示される入力ボックスのHTMLのID, ラベル, 表示する内容を作成する関数名, 投稿タイプ, 表示方法)
+            $default_built_ins = array(
+                'posts' => array('page', 'post',),
+            );
+
+            foreach ($default_built_ins['posts'] as $built_in) {
+                add_meta_box(
+                    'canonical_setting',
+                    'Canonical設定',
+                    array($this, 'insert_meta_fields'),
+                    $built_in,
+                    'normal'
+                );
+            }
+
+            if (isset($this->options['custom_posts'])) {
+                foreach ($this->options['custom_posts'] as $custom_post => $post_chk) {
+                    if ($post_chk == 1) {
+                        add_meta_box(
+                            'canonical_setting',
+                            'Canonical設定',
+                            array($this, 'insert_meta_fields'),
+                            $custom_post, 'normal'
+                        );
+                    }
+                }
+            }
+        }
+
+    }
+
+}
\ No newline at end of file
diff --git a/class/mtee-output-ogp.php b/class/mtee-output-ogp.php
new file mode 100644
index 0000000..cff6e84
--- /dev/null
+++ b/class/mtee-output-ogp.php
@@ -0,0 +1,30 @@
+<?php
+
+if (!defined('ABSPATH')) {
+    exit;
+} // Exit if accessed directly
+
+if (!class_exists('mtee_meta_output_ogp')) {
+
+
+    class mtee_meta_output_ogp {
+        public function __construct() {
+            //GOPのプレフィックスを出力する
+            add_filter('language_attributes', array($this, 'add_html_ogp_prefix'));
+        }
+
+        /**
+         * GOPのプレフィックスを設定する
+         * @param $output
+         * @return string
+         */
+        public function add_html_ogp_prefix($output): string {
+            $output .= $this->create_ogp_prefix();
+            return $output;
+        }
+
+        private function create_ogp_prefix(): string {
+            return ' prefix="og: https://ogp.me/ns#"';
+        }
+    }
+}
\ No newline at end of file