The invention relates to a piston compressor, especially a refrigerant compressor, which has a compression chamber arranged in a compressor block and limited by a cylinder head (10), the cylinder headhas at least one suction valve (23, 24) and at least one pressure valve (21, 22) as well as at least one plate valve arrangement of a valve cover (12). The invention intends to realize low manufacture cost, and good efficiency. Therefore, the valve plate arrangement (16) is formed by a support plate (17) comprising suction valves (23, 24, 26, 27) and pressure valves (18, 19, 21, 22), and the support plate (17) is connected to the valve cover (12) by at least one airtight connecting seam (28, 31), a suction area (22) and a compression area (32) are separated each other by the connecting seam (28, 31), and at least the compression area (29, 30) is sealed relatively to the outside.