A two-stage changeover valve is provided in a vaporized fuel passage connected between a fuel tank and a canister. A valve member is movably accommodated in a fluid passage formed in a valve housing. A valve seat is formed at an inner peripheral wall of the valve housing, so that the valve member is operatively seated on the valve seat. A restricted communication hole is formed in the valve member, so that an upstream side and a downstream side of the valve member are communicated with each other, even when the valve member is seated on the valve seat. The restricted communication hole is formed in a Laval-nozzle shape, so that vaporized fuel passing through the restricted communication hole is accelerated. As a result, a process for depressurizing inner pressure of the vaporized fuel in the fuel tank can be carried out in a shorter time.