Abstract: A control apparatus for controlling a feed or advance movement of a tool relative to a workpiece in a gear cutting machine operating according to a continuous cutting process, comprising a drive for the tool and the workpiece and a hydraulic directional control valve having a slide or spool controlling the infeed of pressurized fluid medium to a feed piston. By means of the feed motion of the feed piston there is moved through a preparatory path which can be adjusted by a control cam carrier or support as well as a machining or processing path which is governed by the control cam.In order to prevent, in the presence of false setting of the preparatory path, damage to the workpiece, tool and machine, there is provided a switch for turning-on and turning-off the drive of the tool and the workpiece and a pressure limiter which can be switched-off and switched-on during the time that there is moved through the machining path and preparatory path, respectively.