A compact fluid compressor embodying a housing formed of a plurality of stacked sections with relatively large fluid flow passageways cast therein and wherein the overall outline of the compressor's housing is substantially rectangular. This arrangement eliminates numerous external piping and the connections needed therefor, found in prior art compressors, and provides a lightweight and good appearing compressor as well as a highly efficient one. The small size, considering the horse power thereof, is due in part to the utilization therein of the Braun mechanism, a counterbalancing and anti-vibration drive mechanism between the power means and the compressor piston or pistons, which mechanism is fully disclosed in Braun U.S. Pat. No. 3,861,222. Even in the two-stage embodiment of the compressor, an inter-cooler, an after-cooler and an inlet fluid (air) filter lie within the above-mentioned outline. Cavities in the housing adjacent to the Braun mechanism enable the strong housing to serve the dual function of walls for the mechanism and walls for the cooling means.