diff --git a/app/Ejaculation.php b/app/Ejaculation.php
index 80fd2b7..399783a 100644
--- a/app/Ejaculation.php
+++ b/app/Ejaculation.php
@@ -22,4 +22,9 @@ class Ejaculation extends Model
     {
         return $this->belongsTo('App\User');
     }
+
+    public function tags()
+    {
+        return $this->belongsToMany('App\Tag')->withTimestamps();
+    }
 }
diff --git a/app/Http/Controllers/EjaculationController.php b/app/Http/Controllers/EjaculationController.php
index ecba43f..ca731c5 100644
--- a/app/Http/Controllers/EjaculationController.php
+++ b/app/Http/Controllers/EjaculationController.php
@@ -2,6 +2,7 @@
 
 namespace App\Http\Controllers;
 
+use App\Tag;
 use App\User;
 use Carbon\Carbon;
 use Validator;
@@ -28,6 +29,7 @@ class EjaculationController extends Controller
             'time' => 'required|date_format:H:i',
             'note' => 'nullable|string|max:500',
             'link' => 'nullable|url',
+            'tags' => 'nullable|string',
         ])->after(function ($validator) use ($request, $inputs) {
             // 日時の重複チェック
             if (!$validator->errors()->hasAny(['date', 'time'])) {
@@ -46,6 +48,15 @@ class EjaculationController extends Controller
             'is_private' => $request->has('is_private') ?? false
         ]);
 
+        $tags = explode(' ', $inputs['tags']);
+        $tagIds = [];
+        foreach ($tags as $tag) {
+            $tag = Tag::firstOrCreate(['name' => $tag]);
+            $tagIds[] = $tag->id;
+        }
+
+        $ejaculation->tags()->sync($tagIds);
+
         return redirect()->route('checkin.show', ['id' => $ejaculation->id])->with('status', 'チェックインしました！');
     }
 
@@ -115,6 +126,7 @@ class EjaculationController extends Controller
     {
         $ejaculation = Ejaculation::findOrFail($id);
         $user = User::findOrFail($ejaculation->user_id);
+        $ejaculation->tags()->detach();
         $ejaculation->delete();
         return redirect()->route('user.profile', ['name' => $user->name])->with('status', '削除しました。');
     }
diff --git a/app/Tag.php b/app/Tag.php
new file mode 100644
index 0000000..7d4cb9a
--- /dev/null
+++ b/app/Tag.php
@@ -0,0 +1,19 @@
+<?php
+
+namespace App;
+
+use Illuminate\Database\Eloquent\Model;
+
+class Tag extends Model
+{
+    //
+
+    protected $fillable = [
+        'name'
+    ];
+
+    public function ejaculations()
+    {
+        return $this->belongsToMany('App\Ejaculation')->withTimestamps();
+    }
+}
diff --git a/database/migrations/2018_01_08_075844_create_tags_table.php b/database/migrations/2018_01_08_075844_create_tags_table.php
new file mode 100644
index 0000000..3693b75
--- /dev/null
+++ b/database/migrations/2018_01_08_075844_create_tags_table.php
@@ -0,0 +1,40 @@
+<?php
+
+use Illuminate\Support\Facades\Schema;
+use Illuminate\Database\Schema\Blueprint;
+use Illuminate\Database\Migrations\Migration;
+
+class CreateTagsTable extends Migration
+{
+    /**
+     * Run the migrations.
+     *
+     * @return void
+     */
+    public function up()
+    {
+        Schema::create('tags', function (Blueprint $table) {
+            $table->increments('id');
+            $table->string('name');
+            $table->timestamps();
+        });
+
+        Schema::create('ejaculation_tag', function (Blueprint $table) {
+            $table->increments('id');
+            $table->integer('ejaculation_id')->index();
+            $table->integer('tag_id')->index();
+            $table->timestamps();
+        });
+    }
+
+    /**
+     * Reverse the migrations.
+     *
+     * @return void
+     */
+    public function down()
+    {
+        Schema::dropIfExists('tags');
+        Schema::dropIfExists('ejaculation_tag');
+    }
+}
diff --git a/resources/views/ejaculation/checkin.blade.php b/resources/views/ejaculation/checkin.blade.php
index 06eb09b..81fe4e2 100644
--- a/resources/views/ejaculation/checkin.blade.php
+++ b/resources/views/ejaculation/checkin.blade.php
@@ -36,7 +36,7 @@
                 </div>
                 <div class="form-row">
                     <div class="form-group col-sm-12">
-                        <input name="tags" type="hidden">
+                        <input name="tags" type="hidden" value="{{ old('tags') }}">
                         <label for="tagInput"><span class="oi oi-tags"></span> タグ</label>
                         <div class="form-control {{ $errors->has('tags') ? ' is-invalid' : '' }}">
                             <ul id="tags" class="list-inline d-inline"></ul>
@@ -112,6 +112,16 @@
                     .join(' ')
             );
         }
+        function insertTag(value) {
+            $('#tags').append('<li class="list-inline-item badge badge-primary" style="cursor: pointer;" data-value="' + value + '"><span class="oi oi-tag"></span> ' + value + ' | x</li>');
+        }
+        var initTags = $('input[name=tags]').val();
+        if (initTags.trim() !== '') {
+            initTags.split(' ').forEach(function (value) {
+                insertTag(value);
+            });
+        }
+
         $('#tagInput').on('keydown', function (ev) {
             var $this = $(this);
             if ($this.val().trim() !== '') {
@@ -119,7 +129,7 @@
                     case 'Tab':
                     case 'Enter':
                     case ' ':
-                        $('#tags').append('<li class="list-inline-item badge badge-primary" style="cursor: pointer;" data-value="' + $this.val().trim() + '">' + $this.val().trim() + ' | x</li>');
+                        insertTag($this.val().trim());
                         $this.val('');
                         updateTags();
                         ev.preventDefault();
diff --git a/resources/views/ejaculation/show.blade.php b/resources/views/ejaculation/show.blade.php
index e50e3c1..56429d0 100644
--- a/resources/views/ejaculation/show.blade.php
+++ b/resources/views/ejaculation/show.blade.php
@@ -34,15 +34,14 @@
                             @endif
                         </div>
                         <!-- tags -->
-                        @if ($ejaculation->is_private) {{-- TODO: タグを付けたら、タグが空じゃないかも判定に加える --}}
+                        @if ($ejaculation->is_private || $ejaculation->tags->isNotEmpty())
                         <p class="mb-2">
                             @if ($ejaculation->is_private)
                                 <span class="badge badge-warning"><span class="oi oi-lock-locked"></span> 非公開</span>
                             @endif
-                            {{--
-                            <span class="badge badge-secondary"><span class="oi oi-tag"></span> 催眠音声</span>
-                            <span class="badge badge-secondary"><span class="oi oi-tag"></span> 適当なタグ</span>
-                            --}}
+                            @foreach ($ejaculation->tags as $tag)
+                                <span class="badge badge-secondary"><span class="oi oi-tag"></span> {{ $tag->name }}</span>
+                            @endforeach
                         </p>
                         @endif
                         <!-- okazu link -->
diff --git a/resources/views/user/profile.blade.php b/resources/views/user/profile.blade.php
index ff9402a..1cd5ed4 100644
--- a/resources/views/user/profile.blade.php
+++ b/resources/views/user/profile.blade.php
@@ -20,15 +20,14 @@
                     @endif
                 </div>
                 <!-- tags -->
-                @if ($ejaculation->is_private) {{-- TODO: タグを付けたら、タグが空じゃないかも判定に加える --}}
+                @if ($ejaculation->is_private || $ejaculation->tags->isNotEmpty())
                     <p class="mb-2">
                         @if ($ejaculation->is_private)
                             <span class="badge badge-warning"><span class="oi oi-lock-locked"></span> 非公開</span>
                         @endif
-                        {{--
-                        <span class="badge badge-secondary"><span class="oi oi-tag"></span> 催眠音声</span>
-                        <span class="badge badge-secondary"><span class="oi oi-tag"></span> 適当なタグ</span>
-                        --}}
+                        @foreach ($ejaculation->tags as $tag)
+                            <span class="badge badge-secondary"><span class="oi oi-tag"></span> {{ $tag->name }}</span>
+                        @endforeach
                     </p>
                 @endif
                 <!-- okazu link -->