To enhance the accuracy in the turn stopping operation and suppress the manufacturing costs.

A piston 16 is installed inside a cylinder tube 15 arranged in the lower part of a housing 11, and a rod for driving 17 is supported on the piston 16. In the spaces 12b and 13b in the upper part of the housing 11, a rod 21 for pickup having a hole 21a is supported by a supporting means 22 and ball spline 23 in such a way as parallel with the rod 17, and a pad 24 is installed at the tip of the rod 21. A stopper receptacle 26 is installed protrusively on the peripheral surface of the rod 17, and a stopper part 27 to abut to the rear surface of the stopper receptacle 26 is secured to the rod 21, and a compression coil spring 28 is installed between the stopper part 27 and supporting member 22. The rotation of the rod 21 is restricted by ball spline 23 in one place, and impact of the rod 21 applied on the work to be processed is relieved by the spring 28.