diff --git a/app/controllers/comments_controller.rb b/app/controllers/comments_controller.rb
new file mode 100644
index 0000000..96d241e
--- /dev/null
+++ b/app/controllers/comments_controller.rb
@@ -0,0 +1,22 @@
+class CommentsController < ApplicationController
+  def index
+    @comments = Comment.all
+  end
+
+  def create
+    post = Post.find(params[:post_id])
+    @comment = post.comments.build(comment_params)
+
+    if @comment.save
+      redirect_to post, notice: 'Comment has been successfully created.'
+    else
+      redirect_to post, alert: 'Hoge!'
+    end
+  end
+
+  private
+
+    def comment_params
+      params.require(:comment).permit(:body).merge(commented_by: current_user)
+    end
+end
diff --git a/app/controllers/posts_controller.rb b/app/controllers/posts_controller.rb
index c17c23c..ec6e4ad 100644
--- a/app/controllers/posts_controller.rb
+++ b/app/controllers/posts_controller.rb
@@ -6,6 +6,7 @@ def index
   end
 
   def show
+    @comment = @post.comments.new
     @comments = @post.comments
   end
 
diff --git a/app/views/posts/show.html.slim b/app/views/posts/show.html.slim
index 6a067f2..5581e6e 100644
--- a/app/views/posts/show.html.slim
+++ b/app/views/posts/show.html.slim
@@ -15,6 +15,10 @@
             .author__created-at.grey-text.text-darken-1
               = @post.created_at
 
+  = form_for @comment, url: post_comments_path(@post) do |f|
+    = f.text_field :body
+    = f.submit
+
   - @comments.each do |comment|
     .comment
       .author
diff --git a/config/routes.rb b/config/routes.rb
index 75883be..4de28bf 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -2,7 +2,7 @@
   root to: 'posts#index'
   resources :users, only: %i( index show )
   resources :posts do
-    resources :comments, only: %i( index )
+    resources :comments, only: %i( index new create )
   end
 
   get 'login', to: 'sessions#new'