An ECU controls a selector valve so as to connect a first pump passage and a second pump passage, and determines whether a fuel vapor leak from a fuel tank is in an allowable range based on a pressure in the fuel tank which is detected by a pressure sensor while a pump is driven to decrease a pressure in the fuel tank. The ECU opens a purge valve, whereby the fuel vapor adsorbed by a canister is introduce into an engine through an intake passage. The ECU controls the selector valve to connect a first pump passage and the second pump passage so as to circulate an atmospheric air in the pump while the purge valve is opened to introduce the fuel vapor into the internal combustion engine, whereby a foreign matter in the pump can be removed.