PURPOSE: To relieve a shock produced during return of fuel, by a method wherein, in a device which injects fuel, providing a lean air-fuel ratio, through a part of injection valves, a given injection valve is previously actuated according to the current number of revolutions of an engine during fuel return after fuel cut.

CONSTITUTION: In a device in which a fuel injection valve 12 is disposed to an intake air branch pipe 11 communicated to a suction port 5 of each cylinder for 4-cylinder engine, ignition is set in the order of #1, #3, #4, and #2. The #1 and #4 cylinders are set as a lean cylinder which provides a leans air-fuel ratio, and the #3 and #2 cylinder are set as a stoiki cylinder which provides an air-fuel ratio near to a theoretical air-fuel ratio. In the internal-combustion engine, when fuel injection is restarted after fuel cut during reduction, the fuel is injected through a fuel injection valve 12 on the lean cylinder side at the fist number N1 of revolutions, to which the number of revolutions of an engine is set, by means of a control device 16. Thereafter, control is effected so that the fuel is injected through the fuel injection valve 12 on the stoiki cylinder side at the second number N2(<N1) of revolutions.