To simplify a structure, reduce the number of parts and assembling man-hours, reduce manufacturing costs, and improve sharpness of the power steering, in a damper valve of a hydraulic power steering device of a vehicle.

In this hydraulic power steering device, a damper valve 10 is installed to one portion on a circuit of hydraulic oil connecting a switch valve in a gearbox with a power cylinder. This damper valve is equipped with a partition member 12 dividing the inside of a valve casing 11 into two chambers, and a shaft member 13 extending through a central portion of the partition member 12. A first valve mechanism 14 allowing only one directional flow of the hydraulic oil is installed to the partition member 12, and a second valve mechanism 15 allowing only other directional flow of the hydraulic oil is installed to the shaft member 13. The first valve mechanism 14 comprises a plurality of communication holes 16 formed on the partition member 12, and a plate spring 17 opening and closing a plurality of the communication holes 16. The second valve mechanism 15 comprises ball-type check valves 19, 20. The other directional flow of the hydraulic oil is an outward flow from the switch valve to the power cylinder.