diff --git a/lib/fluent/plugin/base.rb b/lib/fluent/plugin/base.rb
index 64ec5d0967..601e216b81 100644
--- a/lib/fluent/plugin/base.rb
+++ b/lib/fluent/plugin/base.rb
@@ -72,8 +72,8 @@ def multi_workers_ready?
 
       def string_safe_encoding(str)
         unless str.valid_encoding?
-          log.info "invalid byte sequence is replaced in `#{str}`" if self.respond_to?(:log)
           str = str.scrub('?')
+          log.info "invalid byte sequence is replaced in `#{str}`" if self.respond_to?(:log)
         end
         yield str
       end