Abstract: In a cooling device for a rotary piston compressor, in particular a screw-type compressor, which is part of a refrigerant circuit together with a condenser and an evaporator, coolant of the refrigeration system and oil serving to lubricate bearings as well as to cool and seal the screw-type compressor are injected into the screw-type compressor. In order to cool the oil serving to lubricate the compressor bearings separately and to thereby achieve a more economical functioning of the entire cooling device, it is suggested that only the part of the oil serving to lubricate the bearings of the compressor is cooled as a function of the oil temperature sensed behind the bearings and that a branched stream of coolant is used for this, the stream on its part subsequently being fed to the compressor again.