A fuel vent valve is not shut improperly by the flow of fuel vapor. The
fuel vent valve also prevents fuel from spilling out from filler neck
during filling of a fuel tank. The fuel vent valve includes a casing
having a vent space, a float and a vent device which can be moved up and
down. The vent device includes an upper valve member, which shuts and
opens a communication passage. The upper valve member is located above
the float. A breathing hole and an outer wall of the valve device form a
restricted passage. When the fuel level reaches a first predetermined
level and the valve device rises, the restricted passage increases the
flow resistance to restrict the flow of fuel vapor from the communication
passage to the outside of the fuel tank. When fuel level reaches a second
predetermined level and the valve device rises further, the upper valve
member closes the communication passage.