diff --git a/app/models/admission_code_message.rb b/app/models/admission_code_message.rb
index 934042a..c5d9dbc 100644
--- a/app/models/admission_code_message.rb
+++ b/app/models/admission_code_message.rb
@@ -12,11 +12,22 @@ def initialize(email)
   end
 
   def post
-    ChatMessageSender.new.post_public_message(api_post_body)
+    chat_message_sender = ChatMessageSender.new
+    res = chat_message_sender.post_public_message(api_post_body) if send_to_channel?
+    res = chat_message_sender.post_public_message(api_post_body_direct_message) if send_to_direct_message?
+    res
   end
 
   private
 
+  def send_to_channel?
+    %w[CHANNEL BOTH].include?(ENV.fetch("SEND_MODE"))
+  end
+
+  def send_to_direct_message?
+    %w[DM BOTH].include?(ENV.fetch("SEND_MODE"))
+  end
+
   # @return [Hash] postMessage API post body
   # @see https://api.slack.com/methods/chat.postMessage
   # @see https://github.com/slack-ruby/slack-ruby-client/blob/master/lib/slack/web/api/endpoints/chat.rb
@@ -31,6 +42,16 @@ def api_post_body
       ] }
   end
 
+  def api_post_body_direct_message
+    { icon_emoji: MESSAGES["notification"]["icon"],
+      channel: @email.slack_id,
+      text: "<@#{@email.slack_id}> #{MESSAGES['notification']['text_notification']}",
+      attachments: [
+        color: "good",
+        fields: attachment_fields
+      ] }
+  end
+
   # @return [Array] attachment_field array
   # @private
   def attachment_fields
diff --git a/app/models/chat_message_sender.rb b/app/models/chat_message_sender.rb
index 014beb0..fbe60cb 100644
--- a/app/models/chat_message_sender.rb
+++ b/app/models/chat_message_sender.rb
@@ -14,6 +14,10 @@ def post_public_message(post_body)
     @slack_api_client.chat_postMessage(post_body)
   end
 
+  def post_direct_message(post_body)
+    @slack_api_client.chat_postMessage(post_body)
+  end
+
   # 特定のユーザーだけに見える形で投稿
   # @param post_body [Hash]
   # @see https://api.slack.com/methods/chat.postEphemeral
diff --git a/app/models/slack_message.rb b/app/models/slack_message.rb
index 75e1a2a..bb8d103 100644
--- a/app/models/slack_message.rb
+++ b/app/models/slack_message.rb
@@ -31,10 +31,24 @@ def received_message_post_body
     { icon_emoji: MESSAGES["intarctive"]["icon"],
       channel: @dialog_submission.slack_channel_id,
       user: @dialog_submission.slack_user_id,
-      text: MESSAGES["intarctive"]["text_notification"],
+      text:,
       attachments: [attachment(fields: received_message_attachment_fields)] }
   end
 
+  def text
+    if send_to_direct_message?
+      MESSAGES["intarctive"]["dm_text_notification"]
+    else
+      MESSAGES["intarctive"]["text_notification"]
+    end
+  end
+
+  # @private
+  # @return [Boolean]
+  def send_to_direct_message?
+    %w[DM BOTH].include?(ENV.fetch("SEND_MODE"))
+  end
+
   # @return [Array] attachment_field array
   # @private
   def received_message_attachment_fields
diff --git a/config/messages.sample.yml b/config/messages.sample.yml
index 70397e3..73a9de3 100644
--- a/config/messages.sample.yml
+++ b/config/messages.sample.yml
@@ -14,6 +14,7 @@ dialog:
   <<: *common
 intarctive:
   text_notification: "以下の内容で受け付けました。受け付け完了までしばらくお待ちください :pray:"
+  dm_text_notification: "以下の内容で受け付けました。受け付け完了までしばらくお待ちください :pray: \n受付が完了すると入館IDとバーコードがslackbotで届きます:mailbox_with_mail:"
   <<: *common
 notification:
   text_notification: "入館受付が完了しました :tada:"
diff --git a/config/messages.yml b/config/messages.yml
index 5b4b27f..247dc8d 100644
--- a/config/messages.yml
+++ b/config/messages.yml
@@ -14,6 +14,7 @@ dialog:
   <<: *common
 intarctive:
   text_notification: "以下の内容で受け付けました。受け付け完了までしばらくお待ちください :pray:"
+  dm_text_notification: "以下の内容で受け付けました。受け付け完了までしばらくお待ちください :pray: \n受付が完了すると入館IDとバーコードがslackbotで届きます:mailbox_with_mail:"
   <<: *common
 notification:
   text_notification: "入館受付が完了しました :tada:"
diff --git a/sample.env b/sample.env
index 4f1bd25..110bfe2 100644
--- a/sample.env
+++ b/sample.env
@@ -1,6 +1,6 @@
 # Slack App OAuth Access Token
 SLACK_TOKEN='xoxp-'
-# Slack への通知チャンネル (only public)
+# Slack への通知チャンネル
 SLACK_CHANNEL='#reception'
 # srd-gate.com の認証ユーザー
 SRD_GATE_USERNAME=""
@@ -11,4 +11,6 @@ MAIL_ADDRESS_HOST=""
 # 申請結果を受け取る Email Webhook 用のアドレス（ゲストに届くメール）
 MAIL_ADDRESS_WEBHOOK=""
 # 会社の電話番号（申請に必要）
-COMPANY_TEL="03-1234-5678"
\ No newline at end of file
+COMPANY_TEL="03-1234-5678"
+# 通知の送信先（CHANNEL or DM or BOTH）
+SEND_MODE=""
\ No newline at end of file
diff --git a/spec/app/models/admission_code_message_spec.rb b/spec/app/models/admission_code_message_spec.rb
index 4d69b84..8d71d81 100644
--- a/spec/app/models/admission_code_message_spec.rb
+++ b/spec/app/models/admission_code_message_spec.rb
@@ -3,6 +3,7 @@
 require "spec_helper"
 require_relative "../../../app/models/email"
 require_relative "../../../app/models/admission_code_message"
+require_relative "../../../app/models/chat_message_sender"
 
 describe AdmissionCodeMessage do
   let(:instance) { described_class.new(email) }
@@ -30,6 +31,50 @@
     EMAIL_BODY
   end
 
+  describe "#post" do
+    context "SEND_MODE が CHANNEL の場合" do
+      it "post_public_message が1回呼ばれること" do
+        allow(ENV).to receive(:fetch).with("SEND_MODE").and_return("CHANNEL")
+        allow(ENV).to receive(:fetch).with("SLACK_CHANNEL").and_return("CH15TJXEX")
+        chat_message_sender = instance_double(ChatMessageSender)
+        allow(ChatMessageSender).to receive(:new).and_return(chat_message_sender)
+        allow(chat_message_sender).to receive(:post_public_message)
+
+        instance.post
+
+        expect(chat_message_sender).to have_received(:post_public_message).once
+      end
+    end
+
+    context "SEND_MODE が DM の場合" do
+      it "post_direct_message が1回呼ばれること" do
+        allow(ENV).to receive(:fetch).with("SEND_MODE").and_return("DM")
+        allow(ENV).to receive(:fetch).with("SLACK_CHANNEL").and_return("CH15TJXEX")
+        chat_message_sender = instance_double(ChatMessageSender)
+        allow(ChatMessageSender).to receive(:new).and_return(chat_message_sender)
+        allow(chat_message_sender).to receive(:post_public_message)
+
+        instance.post
+
+        expect(chat_message_sender).to have_received(:post_public_message).once
+      end
+    end
+
+    context "SEND_MODE が BOTH の場合" do
+      it "post_public_message が2回呼ばれること" do
+        allow(ENV).to receive(:fetch).with("SEND_MODE").and_return("BOTH")
+        allow(ENV).to receive(:fetch).with("SLACK_CHANNEL").and_return("CH15TJXEX")
+        chat_message_sender = instance_double(ChatMessageSender)
+        allow(ChatMessageSender).to receive(:new).and_return(chat_message_sender)
+        allow(chat_message_sender).to receive(:post_public_message)
+
+        instance.post
+
+        expect(chat_message_sender).to have_received(:post_public_message).twice
+      end
+    end
+  end
+
   describe "#api_post_body" do
     before do
       allow(ENV).to receive(:fetch).with("SLACK_CHANNEL").and_return("CH15TJXEX")
diff --git a/spec/app/models/slack_message_spec.rb b/spec/app/models/slack_message_spec.rb
index a0c854f..0dd692a 100644
--- a/spec/app/models/slack_message_spec.rb
+++ b/spec/app/models/slack_message_spec.rb
@@ -9,8 +9,9 @@
   let(:instance) { described_class.new }
 
   describe "#received_message_post_body" do
-    context "ok" do
-      it do
+    context "チャンネルに通知する場合" do
+      it "適切なメッセージが通知されること" do
+        allow(ENV).to receive(:fetch).with("SEND_MODE").and_return("CHANNEL")
         modal_submit_fixture = { type: "dialog_submission",
                                  user: { id: "UCKTXCBRB" },
                                  channel: { id: "CH15TJXEX" },
@@ -35,6 +36,32 @@
       end
     end
   end
+  context "DMに通知する場合" do
+    it "適切なメッセージが通知されること" do
+      allow(ENV).to receive(:fetch).with("SEND_MODE").and_return("DM")
+      modal_submit_fixture = { type: "dialog_submission",
+                               user: { id: "UCKTXCBRB" },
+                               channel: { id: "CH15TJXEX" },
+                               submission: { date: "2023/01/01",
+                                             time: "08:00",
+                                             company_name: "SmartHR",
+                                             name: "須磨 英知" } }
+      dialog_submission = SlackDialogSubmission.new(modal_submit_fixture)
+      instance = described_class.new(dialog_submission:)
+
+      expected = {
+        channel: "CH15TJXEX",
+        icon_emoji: ":office:",
+        text: "以下の内容で受け付けました。受け付け完了までしばらくお待ちください :pray: \n受付が完了すると入館IDとバーコードがslackbotで届きます:mailbox_with_mail:",
+        user: "UCKTXCBRB",
+        attachments: [{
+          color: "good",
+          fields: instance.send(:received_message_attachment_fields)
+        }]
+      }
+      expect(instance.send(:received_message_post_body)).to eq expected
+    end
+  end
   describe "#received_message_attachment_fields" do
     context "ok" do
       it do