A rotary distributor device for a hydraulic power steering, which receives oil from a pump and sends the oil selectively to a discharge or to an actuator of the steering in a desired direction, comprises a jacket, a slide, sealedly rotating in the jacket, a series of openings that cross the wall of the jacket, located in front of a series of corresponding openings which cross the wall of the slide, elastic member located between the jacket and the slide configured to maintain the openings of the jacket at the openings of the slide, in which each opening in the jacket includes, in succession starting from the outside, at least one radial hole, a slot lying in a radial plane, arranged symmetrically with respect to the axis of the hole, the width being smaller than the diameter of the hole, and the depth being such as to intersect the hole.