diff --git a/app/services/search_service.rb b/app/services/search_service.rb
index c717c31e5..5eb11f398 100644
--- a/app/services/search_service.rb
+++ b/app/services/search_service.rb
@@ -44,7 +44,7 @@ class SearchService < ApplicationService
     when 'subject' then
       { where: { id: Laboratory.current.subjects.pluck(:id) } }
     when 'course' then
-      { where: { id: Laboratory.current.all_courses } }
+      { where: { id: Laboratory.current.all_courses.pluck(:id) } }
     else
       {}
     end