diff --git a/lib/fluent/command/fluentd.rb b/lib/fluent/command/fluentd.rb
index ed1ad22123..2b2d229a01 100644
--- a/lib/fluent/command/fluentd.rb
+++ b/lib/fluent/command/fluentd.rb
@@ -81,7 +81,6 @@
   opts[:chgroup] = s
 }
 
-opts[:chumask] = 0
 op.on('--umask UMASK', "change umask") {|s|
   opts[:chumask] = s
 }
diff --git a/lib/fluent/supervisor.rb b/lib/fluent/supervisor.rb
index 819877e3a4..4c57048809 100644
--- a/lib/fluent/supervisor.rb
+++ b/lib/fluent/supervisor.rb
@@ -566,6 +566,7 @@ def self.default_options
         setup_path: nil,
         chuser: nil,
         chgroup: nil,
+        chumask: "0",
         root_dir: nil,
         suppress_interval: 0,
         suppress_repeated_stacktrace: true,