Abstract: A power steering apparatus for a vehicle comprising: a hydraulic actuator for supplementing manual steering torque; a first valve means for controlling directions of pressure fluid supplied to the hydraulic actuator in response to manual steering; a second valve means for reducing the supplementing force of the hydraulic actuator by by-passing the pressure fluid; a vehicle speed detecting means for detecting the cruising speed of the vehicle; first switching means responsive to the vehicle speed detecting means for supplying electric energy to the second valve means when the cruising speed exceeds a predetermined value; and second switching means for decreasing electric energy supplied to the second valve means when the second valve means starts to by-pass the pressure fluid.