diff --git a/APIHook.cpp b/APIHook.cpp
index ebc6a9d..2dac90a 100644
--- a/APIHook.cpp
+++ b/APIHook.cpp
@@ -364,6 +364,23 @@ class ChronosFileOpenDialog : public IFileOpenDialog
 				}
 			}
 
+			int maxFileLength = theApp.m_AppSettings.GetMaxUploadFileLength();
+			if (maxFileLength > 0)
+			{
+				WCHAR* ptrFile = NULL;
+				ptrFile = PathFindFileNameW((LPCWSTR)strSelPathOriginal);
+				CString fileName(ptrFile);
+				int fileLength = fileName.GetLength();
+				if (fileLength > maxFileLength)
+				{
+					CString strCaption(theApp.m_strThisAppName);
+					CString strMsg;
+					strMsg.Format(L"ファイル名が長すぎるためアップロードできません。\n\n選択したファイルの名前: %d文字\n指定可能なファイル名の最大値: %d文字", fileLength, maxFileLength);
+					::MessageBoxW(hwndOwner, strMsg, strCaption, MB_OK | MB_ICONWARNING);
+					continue;
+				}
+			}
+
 			if (theApp.m_AppSettings.IsEnableLogging() && theApp.m_AppSettings.IsEnableUploadLogging())
 			{
 				WCHAR* ptrFile = NULL;
@@ -997,6 +1014,21 @@ static BOOL WINAPI Hook_GetOpenFileNameW(
 				}
 			}
 
+			int maxFileLength = theApp.m_AppSettings.GetMaxUploadFileLength();
+			if (maxFileLength > 0)
+			{
+				WCHAR* ptrFile = NULL;
+				ptrFile = PathFindFileNameW(lpofn->lpstrFile);
+				CString fileName(ptrFile);
+				int fileLength = fileName.GetLength();
+				if (fileLength > maxFileLength)
+				{
+					strMsg.Format(L"ファイル名が長すぎるためアップロードできません。\n\n選択したファイルの名前: %d文字\n指定可能なファイル名の最大値: %d文字", fileLength, maxFileLength);
+					::MessageBoxW(lpofn->hwndOwner, strMsg, strCaption, MB_OK | MB_ICONWARNING);
+					continue;
+				}
+			}
+
 			PathRemoveFileSpec(strSelPath.GetBuffer());
 			strSelPath.ReleaseBuffer();
 			theApp.m_strLastSelectUploadFolderPath = strSelPath;
diff --git a/sbcommon.h b/sbcommon.h
index ba242c6..c48bf23 100644
--- a/sbcommon.h
+++ b/sbcommon.h
@@ -951,6 +951,7 @@ class AppSettings
 		WindowCountLimit = 0;
 		EnableMediaAccessByApproval = static_cast<int>(AppSettings::MediaAccessPermission::NO_MEDIA_ACCESS);
 		EnableMediaAccessPermission = static_cast<int>(AppSettings::MediaAccessPermission::NO_MEDIA_ACCESS);
+		MaxUploadFileLength = 0;
 
 		EnableDownloadRestriction = 0;
 		EnableUploadRestriction = 0;
@@ -1035,6 +1036,7 @@ class AppSettings
 		Data.MemoryUsageLimit = MemoryUsageLimit;
 		Data.WindowCountLimit = WindowCountLimit;
 		Data.EnableMediaAccessPermission = EnableMediaAccessPermission;
+		Data.MaxUploadFileLength = MaxUploadFileLength;
 
 		Data.EnableDownloadRestriction = EnableDownloadRestriction;
 		Data.EnableUploadRestriction = EnableUploadRestriction;
@@ -1122,6 +1124,7 @@ class AppSettings
 	int WindowCountLimit;
 	int EnableMediaAccessByApproval; // deprecated
 	int EnableMediaAccessPermission;
+	int MaxUploadFileLength;
 
 	//リダイレクト設定
 	int EnableURLRedirect;
@@ -1229,6 +1232,7 @@ class AppSettings
 		MemoryUsageLimit = 2040;
 		WindowCountLimit = 60;
 		EnableMediaAccessPermission = static_cast<int>(AppSettings::MediaAccessPermission::NO_MEDIA_ACCESS);
+		MaxUploadFileLength = 0;
 
 		/////////////////////////////////////////////////////////////////////////////////////////////////
 		//リダイレクト設定
@@ -1657,6 +1661,17 @@ class AppSettings
 					continue;
 				}
 
+				if (strTemp2.CompareNoCase(_T("MaxUploadFileLength")) == 0)
+				{
+					int iW = 0;
+					iW = _ttoi(strTemp3);
+					if (0 <= iW && iW <= MAX_PATH - 1)
+						MaxUploadFileLength = iW;
+					else
+						MaxUploadFileLength = 0;
+					continue;
+				}
+
 				if (strTemp2.CompareNoCase(_T("EnableDownloadRestriction")) == 0)
 				{
 					EnableDownloadRestriction = (strTemp3 == _T("1")) ? TRUE : FALSE;
@@ -2020,6 +2035,7 @@ class AppSettings
 
 		strRet += _T("# non GUI parameters\n");
 		strRet += EXTVAL(EnableMediaAccessPermission);
+		strRet += EXTVAL(MaxUploadFileLength);
 		strRet += EXTVAL(UploadBasePath);
 		strRet += EXTVAL(ExitMessage);
 		strRet += EXTVAL(unZipMessage);
@@ -2078,6 +2094,7 @@ class AppSettings
 	inline int GetMemoryUsageLimit() { return MemoryUsageLimit; }
 	inline int GetWindowCountLimit() { return WindowCountLimit; }
 	inline int GetMediaAccessPermission() { return EnableMediaAccessPermission; }
+	inline int GetMaxUploadFileLength() { return MaxUploadFileLength; }
 
 	inline BOOL IsEnableDownloadRestriction() { return EnableDownloadRestriction; }
 	inline BOOL IsEnableUploadRestriction() { return EnableUploadRestriction; }