An electronic control unit 9 performs a delay control for extending the period from when an engine stop request is made to when the engine is actually stopped. During non-execution of the delay control, the electronic control unit 9 adjusts the opening degree of a throttle valve 38 according to an accelerator pedal depression degree. During the execution of the delay control, the electronic control unit 9 adjusts the opening degree of a throttle valve 38 such that the opening degree becomes less than the opening degree during the non-execution of the delay control.