A rotary valve that controls a flow rate at which working oil is supplied to and discharged from a hydraulic cylinder (20) that causes a wing (2, 3) to rotate about a rotary shaft (5) includes a rotor (60) that rotates as the wing (2, 3) rotates about the rotary shaft (5), and a first control flow passage (61) and a second control flow passage (65) formed in the rotor (60) to control the flow rate at which the working fluid is supplied to and discharged from the hydraulic cylinder (20), wherein the first control flow passage (61) and the second control flow passage (65) respectively vary a resistance exerted on a flow of the working fluid passing therethrough as the rotor (60) rotates.