diff --git a/gui/include/sessionlog.h b/gui/include/sessionlog.h
index 24e5687..b49b78a 100644
--- a/gui/include/sessionlog.h
+++ b/gui/include/sessionlog.h
@@ -21,7 +21,9 @@
 #include <chiaki/log.h>
 
 #include <QString>
+#include <QMutex>
 
+class QFile;
 class StreamSession;
 
 class SessionLog
@@ -30,15 +32,19 @@ class SessionLog
 
 	private:
 		StreamSession *session;
-		ChiakiLog chiaki_log;
+		ChiakiLog log;
+		QFile *file;
+		QMutex file_mutex;
 
 		void Log(ChiakiLogLevel level, const char *msg);
 
 	public:
 		SessionLog(StreamSession *session, uint32_t level_mask, const QString &filename);
+		~SessionLog();
 
-		ChiakiLog *GetChiakiLog()	{ return &chiaki_log; }
-
+		ChiakiLog *GetChiakiLog()	{ return &log; }
 };
 
+QString CreateLogFilename();
+
 #endif //CHIAKI_SESSIONLOG_H
diff --git a/gui/src/main.cpp b/gui/src/main.cpp
index c145090..faedc7c 100644
--- a/gui/src/main.cpp
+++ b/gui/src/main.cpp
@@ -65,6 +65,7 @@ int main(int argc, char *argv[])
 		StreamSessionConnectInfo connect_info;
 
 		connect_info.log_level_mask = CHIAKI_LOG_ALL & ~CHIAKI_LOG_VERBOSE;
+		connect_info.log_file = CreateLogFilename();
 
 		connect_info.host = host;
 		connect_info.registkey = parser.value(regist_key_option);
diff --git a/gui/src/sessionlog.cpp b/gui/src/sessionlog.cpp
index 0b03b2a..a905a06 100644
--- a/gui/src/sessionlog.cpp
+++ b/gui/src/sessionlog.cpp
@@ -18,19 +18,57 @@
 #include <sessionlog.h>
 #include <chiaki/log.h>
 
+#include <QStandardPaths>
+#include <QDir>
+#include <QRegularExpression>
+#include <QDateTime>
+#include <QFile>
+
+
 static void LogCb(ChiakiLogLevel level, const char *msg, void *user);
 
 SessionLog::SessionLog(StreamSession *session, uint32_t level_mask, const QString &filename)
 	: session(session)
 {
-	chiaki_log_init(&chiaki_log, level_mask, LogCb, this);
+	chiaki_log_init(&log, level_mask, LogCb, this);
 
-	// TODO: file
+	if(filename.isEmpty())
+	{
+		file = nullptr;
+		CHIAKI_LOGI(&log, "Logging to file disabled");
+	}
+	else
+	{
+		file = new QFile(filename);
+		if(!file->open(QIODevice::ReadWrite))
+		{
+			delete file;
+			file = nullptr;
+			CHIAKI_LOGI(&log, "Failed to open file %s for logging", filename.toLocal8Bit().constData());
+		}
+		else
+		{
+			CHIAKI_LOGI(&log, "Logging to file %s", filename.toLocal8Bit().constData());
+		}
+	}
+}
+
+SessionLog::~SessionLog()
+{
+	delete file;
 }
 
 void SessionLog::Log(ChiakiLogLevel level, const char *msg)
 {
 	chiaki_log_cb_print(level, msg, nullptr);
+
+	if(file)
+	{
+		QMutexLocker lock(&file_mutex);
+		// TODO: add timestamp and level
+		file->write(msg);
+		file->write("\n");
+	}
 }
 
 class SessionLogPrivate
@@ -43,4 +81,49 @@ static void LogCb(ChiakiLogLevel level, const char *msg, void *user)
 {
 	auto log = reinterpret_cast<SessionLog *>(user);
 	SessionLogPrivate::Log(log, level, msg);
-}
\ No newline at end of file
+}
+
+#define KEEP_LOG_FILES_COUNT 5
+
+static const QString date_format = "yyyy-MM-dd_HH-mm-ss-zzzz";
+static const QString session_log_wildcard = "chiaki_session_*.log";
+static const QRegularExpression session_log_regex("chiaki_session_(.*).log");
+
+QString CreateLogFilename()
+{
+	auto base_dir = QStandardPaths::writableLocation(QStandardPaths::AppDataLocation);
+	if(base_dir.isEmpty())
+		return QString();
+
+	QDir dir(base_dir);
+	if(!dir.mkpath("log"))
+		return QString();
+	if(!dir.cd("log"))
+		return QString();
+
+	dir.setNameFilters({ session_log_wildcard });
+	auto existing_files = dir.entryList();
+	QVector<QPair<QString, QDateTime>> existing_files_date;
+	existing_files_date.resize(existing_files.count());
+	std::transform(existing_files.begin(), existing_files.end(), existing_files_date.begin(), [](const QString &filename) {
+		QDateTime date;
+		auto match = session_log_regex.match(filename);
+		if(match.hasMatch())
+			date = QDateTime::fromString(match.captured(1), date_format);
+		return QPair<QString, QDateTime>(filename, date);
+	});
+	std::sort(existing_files_date.begin(), existing_files_date.end(), [](const QPair<QString, QDateTime> &a, const QPair<QString, QDateTime> &b) {
+		return a.second > b.second;
+	});
+
+	for(int i=KEEP_LOG_FILES_COUNT; i<existing_files_date.count(); i++)
+	{
+		const auto &pair = existing_files_date[i];
+		if(!pair.second.isValid())
+			break;
+		dir.remove(pair.first);
+	}
+
+	QString filename = "chiaki_session_" + QDateTime::currentDateTime().toString(date_format) + ".log";
+	return dir.absoluteFilePath(filename);
+}
diff --git a/gui/src/streamsession.cpp b/gui/src/streamsession.cpp
index 5a1d286..ba82e48 100644
--- a/gui/src/streamsession.cpp
+++ b/gui/src/streamsession.cpp
@@ -26,7 +26,6 @@
 
 #include <QKeyEvent>
 #include <QAudioOutput>
-#include <QDebug>
 
 #include <cstring>