a hydraulic screw machine including a drive screw and at least one running screw co - operating therewith are arranged inside a housing , the drive screw being united with a shaft extending out through the housing at the high pressure side of the machine and being provided with a balancing piston for balancing a part of the axial force acting on the drive screw and also with a collar which together with a wall portion of the housing forms a hydrostatic axial bearing for taking up the remaining axial force acting on the drive screw . the bearing surfaces of the axial bearing are kept separated by a spring means during starting and similar operating conditions . an axially limitedly movable rolling bearing is mounted in association with the hydrostatic axial bearing and takes up axial forces on the drive screw occurring in certain operating conditions .