BYPASS VALVE AND SUPERCHARGER

Provided is a bypass valve that diverts some of compressed air in a scroll section to an upstream side of the scroll section via a bypass conduit in an open state and sends the compressed air in the scroll section to a downstream side in a closed state, the bypass valve including a valve body that is fittable in a branch hole in which the scroll section communicates with the bypass conduit, and an actuator that moves the valve body between the closed state where the valve body is fitted in the branch hole and the open state where the valve body is away from the branch hole, in which the valve body forms an inner surface along an inner wall of the scroll section in the closed state.