A flow control valve includes a housing, a valve element, a valve-element
urger, a first valve, and a second valve. The first valve closes the
communication between inlet and outlet openings of the housing gradually
when the valve-element urger moves the valve element away from the inlet
opening. The second valve opens the communication between the inlet and
outlet openings when the valve-element urger moves the valve element away
from the inlet opening. The first valve is opened, and the second valve
is closed when a differential pressure between a pressure of the fluid on
an inlet-opening side and a pressure of the fluid on an outlet-opening
side is a predetermined value or less. The second valve opens the
communication between the inlet and outlet openings instantaneously when
the differential pressure is more than a predetermined value.