Abstract: A method of manufacturing a valve rotor is disclosed which forms a hydraulic rotary valve as may be used in a power steering apparatus. A valve rotor includes axially extending grooves formed in its peripheral surface. Each groove is provided with chamfered portions. Each chamfered portion is formed with a first surface which continues to the sidewall of a groove and disposed at an angle with respect to the sidewall, and a second surface which joins the first surface with the arcuate peripheral surface of the rotor. The both surfaces are simultaneously molded by a plastic working.