The piston compressor comprises at least one cylinder (11) and a piston (10) which is guided therein in a non-contact manner and which is linked to a crosshead (6) via a piston rod (8). The piston rod consists of a tube (8) which extends between the crosshead (6) and the piston (10). In the tube there extends a tension rod (9) which can be extended by means of a hydraulic tensioning appliance (30) and which pulls, under pretension, the crosshead and the piston against the tube. <IMAGE>
