diff --git a/app/decorators/user_decorator.rb b/app/decorators/user_decorator.rb
index 8d563a0d32b..ba588c7dece 100644
--- a/app/decorators/user_decorator.rb
+++ b/app/decorators/user_decorator.rb
@@ -5,6 +5,7 @@ module UserDecorator
 
   include Role
   include Retire
+  include ReportStatus
 
   def twitter_url
     "https://twitter.com/#{twitter_account}"
diff --git a/app/decorators/user_decorator/report_status.rb b/app/decorators/user_decorator/report_status.rb
new file mode 100644
index 00000000000..bc024cf5f43
--- /dev/null
+++ b/app/decorators/user_decorator/report_status.rb
@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+module UserDecorator
+  module ReportStatus
+    REPORT_COUNT_LEVELS = {
+      'is-success' => 0..1,
+      'is-primary' => 2..4,
+      'is-warning' => 5..9
+    }.freeze
+
+    LAST_UNCHECKED_REPORT_COUNT = 1
+
+    def user_report_count_class(count)
+      REPORT_COUNT_LEVELS.find { |_, range| range.include?(count) }&.first || 'is-danger'
+    end
+
+    def unchecked_report_message(count, user)
+      if count.zero?
+        "#{user.login_name}さんの日報へ"
+      elsif count == LAST_UNCHECKED_REPORT_COUNT
+        "#{user.login_name}さんの未チェックの日報はこれで最後です。"
+      else
+        "#{user.login_name}さんの未チェックの日報が#{count}件あります。"
+      end
+    end
+  end
+end
diff --git a/app/javascript/stylesheets/application.sass b/app/javascript/stylesheets/application.sass
index 1648020d458..1f5d260153b 100644
--- a/app/javascript/stylesheets/application.sass
+++ b/app/javascript/stylesheets/application.sass
@@ -13,6 +13,7 @@
 @import application/blocks/auth-form/skip-practices
 
 @import application/blocks/cards/card-counts
+@import application/blocks/cards/card-body-main-actions
 
 @import application/blocks/company/company-links
 @import application/blocks/company/company-profile
diff --git a/app/javascript/stylesheets/application/blocks/cards/_card-body-main-actions.sass b/app/javascript/stylesheets/application/blocks/cards/_card-body-main-actions.sass
new file mode 100644
index 00000000000..45c1d1cd5bb
--- /dev/null
+++ b/app/javascript/stylesheets/application/blocks/cards/_card-body-main-actions.sass
@@ -0,0 +1,47 @@
+.card-body-main-actions
+  +position(relative, 1)
+  padding-block: .75rem
+  margin-inline: 1rem
+  border-radius: 4px
+  +media-breakpoint-up(md)
+    padding-inline: 2rem
+    margin-bottom: 1.5rem
+  +media-breakpoint-down(sm)
+    padding-inline: .75rem
+    margin-bottom: 1rem
+  &.is-success
+    background-color: #f8fff2
+    border: 1px solid var(--success)
+    color: var(--success-text)
+  &.is-primary
+    border: 1px solid var(--primary)
+    background-color: #f5f5ff
+    color: var(--primary-text)
+  &.is-warning
+    border: 1px solid var(--warning)
+    background-color: #fff9e7
+    color: var(--warning-text)
+  &.is-danger
+    border: 1px solid var(--danger)
+    background-color: var(--danger-tint)
+    color: var(--danger-text)
+
+.card-body-main-actions__description
+  +text-block(.875rem 1.4)
+  margin-bottom: .75em
+  text-align: center
+
+.card-body-main-actions__items
+  display: flex
+  justify-content: center
+
+.card-body-main-actions__item
+  text-align: center
+  flex: 1
+  +media-breakpoint-up(md)
+    max-width: 16rem
+
+.card-body-main-actions__item-cancel
+  +hover-link-reversal
+  color: var(--muted-text)
+  font-size: .8125rem
diff --git a/app/javascript/stylesheets/application/blocks/event/_event-main-actions.sass b/app/javascript/stylesheets/application/blocks/event/_event-main-actions.sass
index 59be5dfb7ec..49143836221 100644
--- a/app/javascript/stylesheets/application/blocks/event/_event-main-actions.sass
+++ b/app/javascript/stylesheets/application/blocks/event/_event-main-actions.sass
@@ -15,8 +15,8 @@
     color: #4e732e
   &.is-unparticipationed.is-available
     border: 1px solid var(--primary)
-    background-color: #e9f9ff
-    color: #116e94
+    background-color: #f5f5ff
+    color: #28248c
   &.is-unparticipationed.is-capacity-over
     border: 1px solid var(--warning)
     background-color: #fff9e7
@@ -27,7 +27,7 @@
     color: var(--danger)
 
 .event-main-actions__description
-  +text-block(.8125rem 1.4)
+  +text-block(.875rem 1.4)
   margin-bottom: .75em
   text-align: center
 
diff --git a/app/models/cache.rb b/app/models/cache.rb
index b2353db6b19..020f1a9df80 100644
--- a/app/models/cache.rb
+++ b/app/models/cache.rb
@@ -12,6 +12,16 @@ def delete_unchecked_report_count
       Rails.cache.delete 'unchecked_report_count'
     end
 
+    def user_unchecked_report_count(user)
+      Rails.cache.fetch "#{user.id}-user_unchecked_report_count" do
+        Report.unchecked.not_wip.user(user).count
+      end
+    end
+
+    def delete_user_unchecked_report_count(user_id)
+      Rails.cache.delete "#{user_id}-user_unchecked_report_count"
+    end
+
     def unchecked_product_count
       Rails.cache.fetch 'unchecked_product_count' do
         Product.unhibernated_user_products.unchecked.not_wip.count
diff --git a/app/models/check_callbacks.rb b/app/models/check_callbacks.rb
index ac22a01dfe3..f6a902ba67c 100644
--- a/app/models/check_callbacks.rb
+++ b/app/models/check_callbacks.rb
@@ -24,7 +24,9 @@ def after_destroy(check)
   def delete_report_cache(check)
     return unless check.checkable_type == 'Report'
 
+    report = check.checkable
     Cache.delete_unchecked_report_count
+    Cache.delete_user_unchecked_report_count(report.user_id)
   end
 
   def delete_product_cache(check)
diff --git a/app/models/report.rb b/app/models/report.rb
index 4b25cc751a6..6c8c6ebcd25 100644
--- a/app/models/report.rb
+++ b/app/models/report.rb
@@ -60,6 +60,8 @@ class Report < ApplicationRecord # rubocop:todo Metrics/ClassLength
       .default_order
   }
 
+  scope :user, ->(user) { where(user_id: user.id) }
+
   class << self
     def faces
       @faces ||= emotions.keys
diff --git a/app/models/report_callbacks.rb b/app/models/report_callbacks.rb
index ba5ab439fdd..f1f7164e310 100644
--- a/app/models/report_callbacks.rb
+++ b/app/models/report_callbacks.rb
@@ -7,6 +7,7 @@ def after_create(report)
 
   def after_destroy(report)
     Cache.delete_unchecked_report_count
+    Cache.delete_user_unchecked_report_count(report.user_id)
     delete_notification(report)
   end
 
diff --git a/app/models/report_notifier.rb b/app/models/report_notifier.rb
index db793737dbd..79ea5ff383c 100644
--- a/app/models/report_notifier.rb
+++ b/app/models/report_notifier.rb
@@ -4,6 +4,7 @@ class ReportNotifier
   def call(_name, _started, _finished, _unique_id, payload)
     report = payload[:report]
     Cache.delete_unchecked_report_count
+    Cache.delete_user_unchecked_report_count(report.user_id)
 
     return unless report.first_public?
 
diff --git a/app/views/reports/_report_body.html.slim b/app/views/reports/_report_body.html.slim
index 9ff8c49b48f..c926ba159bd 100644
--- a/app/views/reports/_report_body.html.slim
+++ b/app/views/reports/_report_body.html.slim
@@ -6,6 +6,23 @@
     .card-body__description
       .a-long-text.is-md.js-markdown-view(data-taskable-id="#{report.id}" data-taskable-type='Report' data-taskable="#{report.taskable?(current_user).to_s}")
         = report.description
+    - if staff_login?
+      - count = Cache.user_unchecked_report_count(report.user)
+      .card-body-main-actions(class="#{report.user.user_report_count_class(count)} #{mentor_login? ? 'is-only-mentor' : ''}")
+        .card-body-main-actions__description
+          p
+            = report.user.unchecked_report_message(count, report.user)
+        ul.card-body-main-actions__items
+          li.card-body-main-actions__item
+            = link_to user_reports_path(report.user), class: "card-body-main-actions__action a-button is-sm #{report.user.user_report_count_class(count)} is-block", target: '_blank', rel: 'noopener' do
+              | #{report.user.login_name}さんの日報一覧へ
+    - else
+      .card-body-main-actions.p-0
+        ul.card-body-main-actions__items
+          li.card-body-main-actions__item
+            = link_to user_reports_path(report.user), class: 'card-body-main-actions__action a-button is-sm is-secondary is-block', target: '_blank', rel: 'noopener' do
+              | #{report.user.login_name}さんの日報一覧へ
+
   hr.a-border-tint
   = render 'reactions/reactions', reactionable: report
 
diff --git a/test/decorators/user_decorator/report_status.rb b/test/decorators/user_decorator/report_status.rb
new file mode 100644
index 00000000000..e034c4889d8
--- /dev/null
+++ b/test/decorators/user_decorator/report_status.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+
+require 'test_helper'
+require 'active_decorator_test_case'
+
+module UserDecorator
+  class ReportStatusTest < ActiveDecoratorTestCase
+    test 'user_report_count_class' do
+      assert_equal 'is-success', user_report_count_class(0)
+      assert_equal 'is-success', user_report_count_class(1)
+
+      assert_equal 'is-primary', user_report_count_class(2)
+      assert_equal 'is-primary', user_report_count_class(4)
+
+      assert_equal 'is-warning', user_report_count_class(5)
+      assert_equal 'is-warning', user_report_count_class(9)
+
+      assert_equal 'is-danger', user_report_count_class(10)
+      assert_equal 'is-danger', user_report_count_class(100)
+    end
+
+    test 'unchecked_report_message' do
+      user = users(:hajime)
+      assert_equal "#{user.login_name}さんの日報へ", unchecked_report_message(0, user)
+      assert_equal "#{user.login_name}さんの未チェックの日報はこれで最後です。", unchecked_report_message(1, user)
+      assert_equal "#{user.login_name}さんの未チェックの日報が2件あります。", unchecked_report_message(2, user)
+    end
+  end
+end