PURPOSE: To lower a fuel temperature, and prevent overheat of a catalyst by changing opening of a throttle valve to opening set on the basis of a catalyst temperature from opening at fuel cut time when supply of fuel is resumed by stopping a fuel cut.

CONSTITUTION: When an operating condition of an engine EG satisfies conditions such as prescribed conditions that, for example, a cooling water temperature is not less than a prescribed value and a throttle valve 24 is fully closed and engine rotating speed NE is not less than prescribed rotating speed and car speed is not less than prescribed speed, a closing signal is outputted to a solenoid valve 17, and a fuel passage 16 for throw is blocked up. When rotating speed becomes fuel cut restoring rotating speed at such fuel cut time, the throttle valve 24 is opened up to throttle opening set by a three-dimensional map. This throttle opening is set in opening such as a temperature of not overheating a catalyst 42, for example, a catalyst temperature becomes about 800°C, for example, at preset restoring rotating speed.