To prevent the fuel odor leaked from a canister from infiltrating into a cabin.

The fuel injection quantity Ti of an injector 13 is calculated based on the number of revolutions of an engine 1 and various correction factors, and the feedback correction to the fuel injection quantity Ti is calculated based on the output of an air-fuel ratio sensor (O2 sensor 16) to detect the change of the air-fuel ratio of the engine 1. When excessive evaporated gas generated by fuel evaporation is burned in the engine 1, correction can not be performed by the feedback correction, and the evaporation correction is performed by a control unit 40 by calculating the evaporation correction KEVPL, an air conditioner 56 is forcibly switched to the inner air circulation by an air-conditioning control unit 57 which is an inner air/outer air switching means of the air conditioner 56 to prevent the fuel odor leaked from a canister 36 from infiltrating into a cabin.