Abstract: A machine tool is suggested, which has a headstock (111) and at least one tool changer (120). The tool changer (120) moves production tools (116) between a magazine position and a working position, at least one fluid power drive cylinder (1) being associated with it as a drive unit (123). On the drive cylinder (1) a locking device (52) is provided, which when a working pressure of the drive piston (6) drops below a predetermined value produces a mechanical locking action of the drive cylinder piston in relation to the housing. To release the mechanical locking, a setting force due to the working pressure must be overcome.