diff --git a/src/Draw.cpp b/src/Draw.cpp
index 756399fd..e9997cdc 100644
--- a/src/Draw.cpp
+++ b/src/Draw.cpp
@@ -50,8 +50,8 @@ static struct
 
 BOOL Flip_SystemTask(void)
 {
-	static DWORD timePrev;
-	static DWORD timeNow;
+	static unsigned long timePrev;
+	static unsigned long timeNow;
 
 	while (TRUE)
 	{
diff --git a/src/Organya.cpp b/src/Organya.cpp
index 8e6e229f..fe7922be 100644
--- a/src/Organya.cpp
+++ b/src/Organya.cpp
@@ -151,12 +151,12 @@ static const OCTWAVE oct_wave[8] =
 
 BOOL MakeSoundObject8(signed char *wavep, signed char track, signed char pipi)
 {
-	DWORD i,j,k;
+	unsigned long i,j,k;
 	unsigned long wav_tp;	// WAVテーブルをさすポインタ (Pointer to WAV table)
-	DWORD wave_size;	// 256;
-	DWORD data_size;
-	BYTE *wp;
-	BYTE *wp_sub;
+	unsigned long wave_size;	// 256;
+	unsigned long data_size;
+	unsigned char *wp;
+	unsigned char *wp_sub;
 	int work;
 
 	for (j = 0; j < 8; j++)
@@ -185,7 +185,7 @@ BOOL MakeSoundObject8(signed char *wavep, signed char track, signed char pipi)
 				work = *(wavep + wav_tp);
 				work += 0x80;
 
-				*wp_sub = (BYTE)work;
+				*wp_sub = (unsigned char)work;
 
 				wav_tp += 0x100 / wave_size;
 				if (wav_tp > 0xFF)
@@ -310,10 +310,10 @@ signed char wave_data[100][0x100];
 
 BOOL InitWaveData100(void)
 {
-	const DWORD *lpdword;	// リソースのアドレス (Resource address)
+	const unsigned long *lpdword;	// リソースのアドレス (Resource address)
 
 	// リソースの検索 (Search for resources)
-	lpdword = (DWORD*)FindResource("WAVE100", "WAVE", NULL);
+	lpdword = (unsigned long*)FindResource("WAVE100", "WAVE", NULL);
 
 	if (lpdword == NULL)
 		return FALSE;
diff --git a/src/Sound.cpp b/src/Sound.cpp
index 352438df..85fedc91 100644
--- a/src/Sound.cpp
+++ b/src/Sound.cpp
@@ -213,7 +213,7 @@ void PlaySoundObject(int no, int mode)
 	}
 }
 
-void ChangeSoundFrequency(int no, DWORD rate)	// 100がMIN9999がMAXで2195?がﾉｰﾏﾙ (100 is MIN, 9999 is MAX, and 2195 is normal)
+void ChangeSoundFrequency(int no, unsigned long rate)	// 100がMIN9999がMAXで2195?がﾉｰﾏﾙ (100 is MIN, 9999 is MAX, and 2195 is normal)
 {
 	AudioBackend_SetSoundFrequency(lpSECONDARYBUFFER[no], (rate * 10) + 100);
 }
diff --git a/src/WindowsWrapper.h b/src/WindowsWrapper.h
index 0cf8fee3..15b2626c 100644
--- a/src/WindowsWrapper.h
+++ b/src/WindowsWrapper.h
@@ -2,13 +2,8 @@
 
 #include <stdio.h>
 
-typedef int HWND;
-
 typedef int BOOL;
 
-typedef unsigned char BYTE;
-typedef unsigned long DWORD;
-
 #ifndef FALSE
 #define FALSE 0
 #endif