A piston compressor includes a front housing member (12) and a rear housing member (13). A suction chamber (19) and a discharge chamber (20) are defined either in the front housing member (12) or in the rear housing member (13). A cylinder block (15) is accommodated in a space (S) defined by the front housing member (12) and the rear housing member (13) to be isolated from ambient air. Cylinder bores are defined in the cylinder block (15). Pistons (34) are accommodated in the cylinder bores. A drive shaft (18) is connected to each piston (34) and is supported by the cylinder block (15). The front housing member (12) and the rear housing member (13) are connected with each other, and the cylinder block (15) is fixed to one of the housing members (12, 13). The compressor is sealed in an improved manner. <IMAGE>
