diff --git a/api-ref/source/conf.py b/api-ref/source/conf.py
index ce567c6a3..4c0492050 100644
--- a/api-ref/source/conf.py
+++ b/api-ref/source/conf.py
@@ -1,5 +1,3 @@
-# -*- coding: utf-8 -*-
-#
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
 # not use this file except in compliance with the License. You may obtain
 # a copy of the License at
diff --git a/doc/source/conf.py b/doc/source/conf.py
index 5524ffba3..2f14680f6 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
diff --git a/releasenotes/source/conf.py b/releasenotes/source/conf.py
index a5abb8ea7..06378f984 100644
--- a/releasenotes/source/conf.py
+++ b/releasenotes/source/conf.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at