The female screw (8a) is formed on the inner circumference of the forward side of the piston receiving hole (8) in the cylinder body (2) and the movable stopper (9) is screwed into the female screw (8a). The piston (12) is located at the stroke end of the forward side when its end face of the forward side is contact with the end face of the backward side of the movable stopper (9). The rotating knob (4) is rotatably mounted on the end of the forward side of the cylinder body (2). The rotation transmitting pin (16) is projected on the end face of the backward side of the rotating knob. The rotation transmitting hole (9a) is formed on the end face of the forward side of the movable stopper (9). The rotation transmitting pin (16) is slidably inserted into the rotation transmitting hole. When the rotating knob (4) is rotated, the movable stopper (9) is screwed into so that the stroke end position and the moving stroke of the piston (12) can be adjusted.