diff --git a/Gemfile b/Gemfile
index b6b82bad8a49a08dd0cf48c7227a211be7098a6c..45aab1df0f8c817c03dd46e24ceb6272ff88df1b 100644
--- a/Gemfile
+++ b/Gemfile
@@ -133,7 +133,7 @@ gem 'gitlab-markup', '~> 1.6.2'
 gem 'redcarpet', '~> 3.4'
 gem 'commonmarker', '~> 0.17'
 gem 'RedCloth', '~> 4.3.2'
-gem 'rdoc', '~> 4.2'
+gem 'rdoc', '~> 6.0'
 gem 'org-ruby', '~> 0.9.12'
 gem 'creole', '~> 0.5.0'
 gem 'wikicloth', '0.8.1'
diff --git a/Gemfile.lock b/Gemfile.lock
index b0b7bb537a894caa3c4a690e4b48bb4efc8bc379..7a3ed89d803183cecc5b649b0254ff6a4587a7ca 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -694,8 +694,7 @@ GEM
       ffi
     rbnacl-libsodium (1.0.11)
       rbnacl (>= 3.0.1)
-    rdoc (4.2.2)
-      json (~> 1.4)
+    rdoc (6.0.4)
     re2 (1.1.1)
     recaptcha (3.0.0)
       json
@@ -1124,7 +1123,7 @@ DEPENDENCIES
   rblineprof (~> 0.3.6)
   rbnacl (~> 4.0)
   rbnacl-libsodium
-  rdoc (~> 4.2)
+  rdoc (~> 6.0)
   re2 (~> 1.1.1)
   recaptcha (~> 3.0)
   redcarpet (~> 3.4)
diff --git a/changelogs/unreleased/46849-update-rdoc-to-6-0-4.yml b/changelogs/unreleased/46849-update-rdoc-to-6-0-4.yml
new file mode 100644
index 0000000000000000000000000000000000000000..cf0436df1a78087486f63a226477a380c05d4903
--- /dev/null
+++ b/changelogs/unreleased/46849-update-rdoc-to-6-0-4.yml
@@ -0,0 +1,5 @@
+---
+title: Update rdoc to 6.0.4
+merge_request: 19167
+author: Takuya Noguchi
+type: other