diff --git a/app/controllers/events_controller.rb b/app/controllers/events_controller.rb
index 46c3cd475..a065d0985 100644
--- a/app/controllers/events_controller.rb
+++ b/app/controllers/events_controller.rb
@@ -6,7 +6,10 @@ def index
 
     respond_to do |format|
       format.html
-      format.json { render json: @upcoming_events }
+      format.json {
+        # DojoMap: https://map.coderdojo.jp
+        render json: UpcomingEvent.for_dojo_map
+      }
     end
   end
 end
diff --git a/app/models/upcoming_event.rb b/app/models/upcoming_event.rb
index 30f989f96..5656945b2 100644
--- a/app/models/upcoming_event.rb
+++ b/app/models/upcoming_event.rb
@@ -34,6 +34,28 @@ def group_by_keyword(keyword)
         merge(Dojo.default_order).
         where('event_title like(?)', "%#{keyword}%")
     end
+
+    def for_dojo_map
+      result = []
+      list_of_dojo_and_events = eager_load(dojo_event_service: :dojo)
+        .since(Time.zone.today)
+        .merge(Dojo.default_order)
+        .group_by { |event| event.dojo_event_service.dojo }
+
+      list_of_dojo_and_events.each do |dojo, events|
+        event = events.sort_by(&:event_at).first
+        result << {
+          id:   dojo.id,
+          name: dojo.name,
+          url:  dojo.url,
+          event_title: event[:event_title],
+          event_date:  event[:event_at],
+          event_url:   event[:event_url],
+        }
+      end
+
+      result
+    end
   end
 
   def catalog