diff --git a/backend/app/models/tag.rb b/backend/app/models/tag.rb
index 137afff..69c6c46 100644
--- a/backend/app/models/tag.rb
+++ b/backend/app/models/tag.rb
@@ -46,6 +46,12 @@ class Tag < ApplicationRecord
     end
   end
 
+  def self.no_deerjikist
+    @no_deerjikist ||= Tag.find_or_initialize_by(name: 'ニジラー情報なし') do |tag|
+      tag.category = 'meta'
+    end
+  end
+
   def self.normalise_tags tag_names, with_tagme: true
     tags = tag_names.map do |name|
       pf, cat = CATEGORY_PREFIXES.find { |p, _| name.start_with?(p) } || ['', nil]
@@ -58,6 +64,7 @@ class Tag < ApplicationRecord
       end
     end
     tags << Tag.tagme if with_tagme && tags.size < 20 && tags.none?(Tag.tagme)
+    tags << Tag.no_deerjikist if tags.all? { |t| t.category != 'deerjika' }
     tags.uniq
   end
 
diff --git a/backend/lib/tasks/sync_nico.rake b/backend/lib/tasks/sync_nico.rake
index a8601c5..026e8f8 100644
--- a/backend/lib/tasks/sync_nico.rake
+++ b/backend/lib/tasks/sync_nico.rake
@@ -53,6 +53,7 @@ namespace :nico do
           end
           tags_to_add << Tag.tagme if post.tags.size < 20
           tags_to_add << Tag.bot
+          tags_to_add << Tag.no_deerjikist if post.tags.all? { |t| t.category != 'deerjikist' }
           post.tags = (post.tags + tags_to_add).uniq
         end
       end