To prevent fluid from changing in flow rate, when the turning movement angle of a flow regulating section is a prescribed value, even if the fluid pressure changes by a constant rate in forward and backward direction.

This flow control valve controls the flow rate of the fluid by changing the flow passage area by turningly moving a flow regulating section 4 against a casing 2. When the turning movement angle of a flow adjust section 4 against the casing 2 is a prescribed value, the flow passage area flowing fluid to the backward direction changes only a predetermined value against the flow passage area flowing fluid in the forward direction. For example, even if the fluid pressure in the backward direction is lower against the fluid pressure in the forward direction, if the flow passage area is preset to increase only by the rate in response to the reduced quantity, the flow rate of the fluid is not changed whether in the forward or the backward direction.