Abstract: There are provided a housing that has a generally cylindrical-shaped internal circumferential surface, a housing passage that includes a high-pressure gas passage and a low-pressure gas passage which are formed on the housing surface, a generally cylindrical-shaped rotor that is supported by bearings, and which rotates with a micro-clearance away from the internal circumferential surface of the housing without touching the housing, and a rotor passage that is formed inside the rotor, and through which gas flows at the time its openings align with the valve housing passage. Load to the rotating axis of the rotor due to the pressure of the supplied gas to the valve is cancelled, and the clearance between the rotor and the housing are maintained at a proper level, by installing pluralities of high-pressure gas supply ports and low-pressure gas supply ports of the housing in symmetrical positions relative to the rotating axis of the rotor.