diff --git a/app/controllers/memos_controller.rb b/app/controllers/memos_controller.rb
new file mode 100644
index 0000000..8719588
--- /dev/null
+++ b/app/controllers/memos_controller.rb
@@ -0,0 +1,23 @@
+class MemosController < ApplicationController
+  def new
+    @book = Book.find(params[:book_id])
+    @memo = @book.memos.new
+  end
+
+  def create
+    @book = Book.find(params[:book_id])
+    @memo = @book.memos.new(params[:memo])
+    if @memo.save
+      redirect_to book_path(@book), :notice => "added memo"
+    else
+      render :new
+    end
+  end
+
+  def destroy
+    @book = Book.find(params[:book_id])
+    @memo = @book.memos.find(params[:id])
+    @memo.destroy
+    redirect_to book_path(@book)
+  end
+end
diff --git a/app/models/book.rb b/app/models/book.rb
index 95c42dd..566c9cc 100644
--- a/app/models/book.rb
+++ b/app/models/book.rb
@@ -1,5 +1,6 @@
 # encoding: UTF-8
 class Book < ActiveRecord::Base
+  has_many :memos , :dependent => :destroy
   attr_accessible :memo, :purchased_on, :title
   validates :title, :presence => true
 
diff --git a/app/models/memo.rb b/app/models/memo.rb
new file mode 100644
index 0000000..248d358
--- /dev/null
+++ b/app/models/memo.rb
@@ -0,0 +1,4 @@
+class Memo < ActiveRecord::Base
+  attr_accessible :book_id, :text
+  validates_length_of :text , :maximum => 100
+end
diff --git a/app/views/books/show.html.erb b/app/views/books/show.html.erb
index 23005ab..75a0b00 100644
--- a/app/views/books/show.html.erb
+++ b/app/views/books/show.html.erb
@@ -7,9 +7,14 @@
 
 <p>
   <b>Memo:</b>
-  <%= @book.memo %>
+  <div><%= @book.memo %></div>
+  <% @book.memos.each do |m| %> 
+    <div>
+      <%= m.text %> |
+      <%= link_to "delete", book_memo_path(:book_id => @book.id, :id => m.id), :confirm => "OK？", :method => :delete %>
+    </div>
+  <% end %>
 </p>
-
 <p>
   <b>Purchased on:</b>
   <%= @book.purchased_on %>
@@ -17,4 +22,5 @@
 
 
 <%= link_to 'Edit', edit_book_path(@book) %> |
-<%= link_to 'Back', books_path %>
+<%= link_to 'Back', books_path %> |
+<%= link_to 'add memo', new_book_memo_path(@book) %>
diff --git a/app/views/memos/new.html.erb b/app/views/memos/new.html.erb
new file mode 100644
index 0000000..b90d647
--- /dev/null
+++ b/app/views/memos/new.html.erb
@@ -0,0 +1,5 @@
+<div>title <%= @book.title %></div>
+<%= form_for @memo, :url => book_memos_path do |f| %>
+  memo <%= f.text_field :text %>
+  <%= f.submit %>
+<% end %>
diff --git a/config/routes.rb b/config/routes.rb
index f3d38ab..32492b6 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -1,5 +1,7 @@
 BookMemo2::Application.routes.draw do
-  resources :books
+  resources :books do
+    resources :memos
+  end
 
   # The priority is based upon order of creation:
   # first created -> highest priority.
diff --git a/db/migrate/20120615023422_create_memos.rb b/db/migrate/20120615023422_create_memos.rb
new file mode 100644
index 0000000..0e64653
--- /dev/null
+++ b/db/migrate/20120615023422_create_memos.rb
@@ -0,0 +1,10 @@
+class CreateMemos < ActiveRecord::Migration
+  def change
+    create_table :memos do |t|
+      t.integer :book_id
+      t.text :text
+
+      t.timestamps
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 5fc61c2..5465c6c 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended to check this file into your version control system.
 
-ActiveRecord::Schema.define(:version => 20120526050801) do
+ActiveRecord::Schema.define(:version => 20120615023422) do
 
   create_table "books", :force => true do |t|
     t.string   "title"
@@ -21,4 +21,11 @@
     t.datetime "updated_at",   :null => false
   end
 
+  create_table "memos", :force => true do |t|
+    t.integer  "book_id"
+    t.text     "text"
+    t.datetime "created_at", :null => false
+    t.datetime "updated_at", :null => false
+  end
+
 end
diff --git a/spec/factories/memos.rb b/spec/factories/memos.rb
new file mode 100644
index 0000000..d618e74
--- /dev/null
+++ b/spec/factories/memos.rb
@@ -0,0 +1,8 @@
+# Read about factories at https://github.com/thoughtbot/factory_girl
+
+FactoryGirl.define do
+  factory :memo do
+    book_id 1
+    text "MyText"
+  end
+end
diff --git a/spec/models/memo_spec.rb b/spec/models/memo_spec.rb
new file mode 100644
index 0000000..14c285e
--- /dev/null
+++ b/spec/models/memo_spec.rb
@@ -0,0 +1,16 @@
+require 'spec_helper'
+
+describe Memo do
+  describe "validate" do
+    context "in limit" do
+      text = "a" * 100
+      subject { Memo.new(:text => text).valid? }
+      it { should be_true }
+    end
+    context "limit over" do
+      text = "a" * (100+1)
+      subject { Memo.new(:text => text).valid? }
+      it { should be_false }
+    end
+  end
+end
diff --git a/spec/requests/books_spec.rb b/spec/requests/books_spec.rb
index 37522b7..1985836 100644
--- a/spec/requests/books_spec.rb
+++ b/spec/requests/books_spec.rb
@@ -37,4 +37,40 @@
       end
     end
   end
+
+  describe '/books/:id/memos/new' do
+    let!(:book){ FactoryGirl.create :book }
+    subject { page }
+
+    before { visit "/books/#{book.id}/memos/new" }
+    context "post memo" do
+      before do
+        fill_in "memo_text" , with: "test1"
+        click_on "Create Memo"
+      end
+
+      it "transit page" do
+        current_path.should == book_path(book)
+      end
+
+      it "さっきのとうこうあること" do
+        should have_content("test1")
+      end
+    end
+
+    context "role2" do
+      before do
+        fill_in "memo_text", with: "test2"
+        click_on "Create Memo"
+      end
+
+      it "transit page" do
+        current_path.should == book_path(book)
+      end
+
+      it "さっきのとうこうあること" do
+        should have_content("test2")
+      end
+    end
+  end
 end