102 being located at the top of the discharge hole 102 the disc valve 103 which is used for closing the discharge hole 102 helps the refrigerant to be compressed by closing the discharge hole with its own weight at the time of the discharge stroke and helps the refrigerant to be discharged as the disc valve 103 is raised by the pressure when the compressive force inside the cylinder exceeds the disc valve weight preferably the disc valve 103 is shaped and dimensioned to be bigger than the diameter of the discharge hole 102 so that it can close the discharge hole 102 and may take the shape of a disc although it is preferred that the shape corresponds to the shape of the discharge hole 102 the stopper 105 is disposed on the top of the discharge valve 103 of the discharge hole 102 and restricts the height the disc valve 103 can be raised when the disc valve 103 is raised by the pressure of the refrigerant during the discharge stroke additionally the middle of the stopper has a through hole 105 a communicating with the discharge hole 102 for smooth flow of the discharged refrigerant each guiding pin 107 having a cylindrical shape fastens the stopper to the valve plate 105 so.