A brake cylinder is disclosed featuring a reduction of weight and a construction for reducing a tendency to vibrate. The piston (11), serving for the brake actuation, is formed out of a plastic mold part and is furnished with a simplified guiding of the piston. A pressure piece (44) serves for the transfer of the braking force, and is formed at the brake cylinder as a plastic mold part for allowing a relatively large distance from the brake drum. The new brake cylinder can be used advantageously for vehicles with wedge expanding brakes, where the brake force is transmitted by and applied with a pressure agent.