A screw displacement pump is provided. The screw displacement pump is of single-entry, double-shaft construction with an external bearing of the two screw shafts. A pump housing encloses the screw shafts by forming feed chambers and externally delimiting the feed chambers with its internal shell surface, as well as a suction chamber for the medium to be induced and a pressure chamber to accommodate the medium pumped by the screw shafts. The pump housing is inserted into a pressure housing and attached to the pressure housing, so that the pressure chamber encloses the pump, at least in part.