A machine tool includes: a hydraulic pump that supplies pressure oil; a fixture plate that positions a workpiece; a fixture base that detachably holds the fixture plate and that moves relative to a tool during machining; a hydraulic cylinder performs an attaching/removing operation for attaching or removing the fixture plate to or from the fixture base; an accumulator that accumulates the pressure oil from the hydraulic pump and that supplies the pressure oil to the hydraulic cylinder; and a manual valve that is manually switched to supply the pressure oil in the accumulator to the hydraulic cylinder to thereby control the attaching/removing operation of the hydraulic cylinder.