To provide a hydraulic torque reducing type butterfly valve capable of reducing operation torque of a valve element in intermediate opening.

The valve element 4 rotating around an axis of a valve rod 3 is arranged at the inside of a valve box 2. A guide body 5 is arranged so as to erect on a valve element surface 4a of the valve element 4 located on a downstream side of the axis of the valve rod 3 in the intermediate opening. Fluid flowing along the valve element surface 4a is guided in a direction away from the valve element surface 4a by the guide body 5. Torque of an open direction is generated in the valve element 4 by the reaction and operation torque of the valve element 4 in the intermediate opening is reduced.