diff --git a/lib/fluent/plugin/file_wrapper.rb b/lib/fluent/plugin/file_wrapper.rb
index e99928b11a..3314c1ddf0 100644
--- a/lib/fluent/plugin/file_wrapper.rb
+++ b/lib/fluent/plugin/file_wrapper.rb
@@ -14,6 +14,8 @@
 #    limitations under the License.
 #
 
+require 'fluent/win32'
+
 module Fluent
   module FileWrapper
     def self.open(path, mode='r')
@@ -35,25 +37,6 @@ def self.stat(path)
     end
   end
 
-  module Win32API
-    require 'fiddle/import'
-    require 'fiddle/types'
-    extend Fiddle::Importer
-
-    if RUBY_PLATFORM.split('-')[-1] == "ucrt"
-      MSVCRT_DLL = 'ucrtbase.dll'
-    else
-      MSVCRT_DLL = 'msvcrt.dll'
-    end
-
-    dlload MSVCRT_DLL, "kernel32.dll"
-    include Fiddle::Win32Types
-
-    extern "intptr_t _get_osfhandle(int)"
-    extern "BOOL GetFileInformationByHandle(HANDLE, void *)"
-    extern "BOOL GetFileInformationByHandleEx(HANDLE, int, void *, DWORD)"
-  end
-
   class WindowsFile
     include File::Constants
 
@@ -64,7 +47,7 @@ class WindowsFile
     def initialize(path, mode='r')
       @path = path
       @io = File.open(path, mode2flags(mode))
-      @file_handle = Win32API._get_osfhandle(@io.to_i)
+      @file_handle = Win32._get_osfhandle(@io.to_i)
       @io.instance_variable_set(:@file_index, self.ino)
       def @io.ino
         @file_index
@@ -84,7 +67,7 @@ def close
     def ino
       by_handle_file_information = '\0'*(4+8+8+8+4+4+4+4+4+4)   #72bytes
 
-      unless Win32API.GetFileInformationByHandle(@file_handle, by_handle_file_information)
+      unless Win32.GetFileInformationByHandle(@file_handle, by_handle_file_information)
         return 0
       end
 
@@ -138,7 +121,7 @@ def delete_pending
       bufsize = 1024
       buf = '\0' * bufsize
 
-      unless Win32API.GetFileInformationByHandleEx(@file_handle, file_standard_info, buf, bufsize)
+      unless Win32.GetFileInformationByHandleEx(@file_handle, file_standard_info, buf, bufsize)
         return false
       end
 
diff --git a/lib/fluent/win32.rb b/lib/fluent/win32.rb
new file mode 100644
index 0000000000..1d89347d53
--- /dev/null
+++ b/lib/fluent/win32.rb
@@ -0,0 +1,38 @@
+#
+# Fluentd
+#
+#    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
+#
+#        http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS,
+#    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#    See the License for the specific language governing permissions and
+#    limitations under the License.
+#
+
+require 'fluent/env'
+
+module Fluent
+  module Win32
+    require 'fiddle/import'
+    require 'fiddle/types'
+    extend Fiddle::Importer
+
+    if RUBY_PLATFORM.split('-')[-1] == "ucrt"
+      MSVCRT_DLL = 'ucrtbase.dll'
+    else
+      MSVCRT_DLL = 'msvcrt.dll'
+    end
+
+    dlload MSVCRT_DLL, "kernel32.dll"
+    include Fiddle::Win32Types
+
+    extern "intptr_t _get_osfhandle(int)"
+    extern "BOOL GetFileInformationByHandle(HANDLE, void *)"
+    extern "BOOL GetFileInformationByHandleEx(HANDLE, int, void *, DWORD)"
+  end if Fluent.windows?
+end