diff --git a/lib/fluent/config/types.rb b/lib/fluent/config/types.rb
index ff61a09ab5..b6b0e97657 100644
--- a/lib/fluent/config/types.rb
+++ b/lib/fluent/config/types.rb
@@ -199,9 +199,9 @@ def self.enum_value(val, opts = {}, name = nil)
 
     def self.hash_value(val, opts = {}, name = nil)
       return nil if val.nil?
-      val = Config.process_env_vars(val)
 
       param = if val.is_a?(String)
+                val = Config.process_env_vars(val)
                 val.start_with?('{') ? JSON.parse(val) : Hash[val.strip.split(/\s*,\s*/).map{|v| v.split(':', 2)}]
               else
                 val
@@ -227,9 +227,9 @@ def self.hash_value(val, opts = {}, name = nil)
 
     def self.array_value(val, opts = {}, name = nil)
       return nil if val.nil?
-      val = Config.process_env_vars(val)
 
       param = if val.is_a?(String)
+                val = Config.process_env_vars(val)
                 val.start_with?('[') ? JSON.parse(val) : val.strip.split(/\s*,\s*/)
               else
                 val