A tank passage has one end connected to a fuel tank. A purge passage has one end connected to a canister and the other end connected to an intake passage. An atmospheric passage has one end connected to the canister and the other end communicated with the atmosphere. A purge valve opens and closes the purge passage. An atmospheric valve opens and closes an atmospheric passage. A tank switch valve opens and closes the tank passage. A pressure sensor detects pressure in the purge passage and outputs a signal corresponding to the detected pressure. An abnormality detection portion executes an abnormality detection processing that detects a clog abnormality based on a signal from a pressure sensor when the tank switch valve is activated in a state in which the purge valve and the atmospheric valve are closed, after driving of an engine is stopped.