To provide a reciprocating refrigerant compressor which can prevent surely and over a long period a delay of opening of a suction valve when a suction stroke is started.

This reciprocating refrigerant compressor comprises: a cylinder block 1 having a cylinder bore 6; a piston 7 movably received in the cylinder bore 6; a compression chamber 14 formed in the cylinder bore 6, a rear head 3 formed with a suction chamber 13 temporarily accumulating refrigerant gas sucked to the compression chamber 14 to be connected to one end face of the cylinder block 1; a valve plate 2 arranged between the compression chamber 14 and the suction chamber 13 to be formed with a suction port 60 for guiding the refrigerant gas in the suction chamber 13 to the compression chamber 14; and a suction valve 70 opening/closing the suction port 60. An elastic thin piece 80 pulling the suction valve 70 into the compression chamber 14, when the piston 7 is transferred from a delivery stroke to a suction stroke, is also provided in a top surface 7c of the piston 7.