To easily and appropriately conduct prescribed working appropriately corresponding to a various required working quantity of a work.

A first piston 15 undertakes pumping function with power of a main body housing 1, a second piston 20 having a diameter larger than the first piston is intermittently advanced bit by bit, working by a tool 51 is processed bit by bit. At a prescribed working quantity or the max working quantity, a hydraulic oil in a second cylinder chamber 19 is returned from three drain passages 33, 35, 37 respectively having a manual stop valve 34, a high pressure regulating valve 36, automatic stop valve 38 to an oil tank 24, stroke control of the second piston 20 is precisely conducted, thus, appropriate working can be done.