A valve plate includes a suction port to which gas to be compressed in a compression chamber flows in and a discharge port from which gas compressed in the compression chamber is discharged, a projection that appears from the discharge port with the reciprocating movement of the piston is arranged at a position facing the discharge port at a distal end face of the piston, and the projection includes a flat surface extending parallel to a reciprocating direction of the piston, so that a highly efficient hermetic type compressor that reduces the dead volume of the discharge port and reduces the loss in the compression chamber and the discharge port is provided.