A compressor C has a construction comprising a cylinder block 1 in which cylinder bores 1a are formed, a front housing 2 and a rear housing 4 which are arranged at the front and at the rear, respectively, of the cylinder block 1. Pistons 20 which are accommodated in each cylinder bore 1a so as to be able to reciprocate, are connected to the cam plate 12, which connects to a drive shaft 6 so as to be able to integrally rotate, so as to operate, and the pistons 20 compress refrigerant gas according to the rotation of the drive shaft 6. A suction muffler 40, a discharge muffler 41 and a control valve 31 are provided between the cylinder bores 1a in the cylinder block 1. Further, a unit 60 which comprises a discharge check valve and an oil separator is disposed in the suction muffler 40.