To provide a flow control valve capable of restraining generation of caviation by making a fluid flow in a central side of a valve casing and a pipe end part even when flowing in a small amount and capable of preventing damage of the valve casing and a pipe.

An outer valve element 5 and an inner valve element 6 rotating to opposite directions around an axis of a valve rod 4 are arranged inside the valve casing 1. Sliding surfaces of the valve elements 5 and 6 confronting to each other are formed in an arc shaped curved surface. Valve body ports 7 and 8 and closing parts 9 and 10 are formed on the valve elements 5 and 6. The valve elements 5 and 6 rotate between a full opening position wherein the valve element ports 7 and 8 confront a valve casing port 2 and a full closing position wherein the closing parts 9 and 10 confront the valve casing port 2.