An actuator, comprising a housing which contains a screw mechanism and a motor which is drivably connected to the screw mechanism, the screw mechanism providing a linear movement in response to a rotational movement of the motor, and comprising a screw and a nut, one of which is supported rotatably with respect to the housing by means of a rolling element bearing, and support means which extend axially with respect to the screw mechanism, the support means engaging the housing and supporting the screw mechanism so as to take up the axial loads exerted on the screw mechanism, wherein the support means comprise a shaft or tube member which is stationary fixed to the housing, one of a nut and screw being rotationally supported with respect to the shaft or tube member, and the support bearing is a four-point contact bearing, the loading angle of the pair of contact points which take up the axial compressive force of the screw mechanism being smaller than the other loading angle.