diff --git a/CMakeLists.txt b/CMakeLists.txt
index ab401a3..e15fc09 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,6 +10,11 @@ endif()
 include_directories(include)
 set(KABUFUDA_INCLUDE_DIR ${CMAKE_CURRENT_SOURCE_DIR}/include CACHE PATH "kabufuda include path" FORCE)
 
+unset(PLAT_SRCS)
+if(WIN32)
+list(APPEND PLAT_SRCS lib/kabufuda/winsupport.cpp include/kabufuda/winsupport.hpp)
+endif()
+
 add_library(kabufuda STATIC
     include/kabufuda/Constants.hpp
     include/kabufuda/BlockAllocationTable.hpp lib/kabufuda/BlockAllocationTable.cpp
@@ -18,7 +23,8 @@ add_library(kabufuda STATIC
     include/kabufuda/File.hpp lib/kabufuda/File.cpp
     include/kabufuda/Util.hpp lib/kabufuda/Util.cpp
     include/kabufuda/SRAM.hpp lib/kabufuda/SRAM.cpp
-    include/kabufuda/WideStringConvert.hpp lib/kabufuda/WideStringConvert.cpp)
+    include/kabufuda/WideStringConvert.hpp lib/kabufuda/WideStringConvert.cpp
+    ${PLAT_SRCS})
 
 if (NOT TARGET hecl)
     add_subdirectory(test)
diff --git a/include/kabufuda/winsupport.hpp b/include/kabufuda/winsupport.hpp
new file mode 100644
index 0000000..1371532
--- /dev/null
+++ b/include/kabufuda/winsupport.hpp
@@ -0,0 +1,14 @@
+#ifndef _HECL_WINSUPPORT_H_
+#define _HECL_WINSUPPORT_H_
+
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN 1
+#endif
+#ifndef NOMINMAX
+#define NOMINMAX 1
+#endif
+#include "windows.h"
+
+void* memmem(const void *haystack, size_t hlen, const void *needle, size_t nlen);
+
+#endif // _HECL_WINSUPPORT_H_
diff --git a/lib/kabufuda/winsupport.cpp b/lib/kabufuda/winsupport.cpp
new file mode 100644
index 0000000..e004d9a
--- /dev/null
+++ b/lib/kabufuda/winsupport.cpp
@@ -0,0 +1,36 @@
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <string>
+#include "hecl/winsupport.hpp"
+
+/*
+* The memmem() function finds the start of the first occurrence of the
+* substring 'needle' of length 'nlen' in the memory area 'haystack' of
+* length 'hlen'.
+*
+* The return value is a pointer to the beginning of the sub-string, or
+* NULL if the substring is not found.
+*/
+void *memmem(const void *haystack, size_t hlen, const void *needle, size_t nlen)
+{
+    int needle_first;
+    const uint8_t *p = static_cast<const uint8_t*>(haystack);
+    size_t plen = hlen;
+
+    if (!nlen)
+        return NULL;
+
+    needle_first = *(unsigned char *)needle;
+
+    while (plen >= nlen && (p = static_cast<const uint8_t*>(memchr(p, needle_first, plen - nlen + 1))))
+    {
+        if (!memcmp(p, needle, nlen))
+            return (void *)p;
+
+        p++;
+        plen = hlen - (p - static_cast<const uint8_t*>(haystack));
+    }
+
+    return NULL;
+}