A cylinder in a suction stroke is identified whenever a predetermined crank angle position signal is generated for each cylinder of a multicylinder IC engine and a first fuel quantity calculated on the basis of an intake air quantity. A representing an engine load and the number of revolutions N of the engine is jetted and supplied to the cylinder which has been identified to be in a suction stroke. A cylinder is identified in a suction stroke for making asyn. injection, whenever a second crank angle position signal closer to the upper dead point than the first predetermined crank angle position signal is generated. A throttle opening at intervals of a predetermined time Ts is detected to calculate the change quantity delta theta of the throttle opening. - A second fuel quantity corresp. to this change quantity, when the quantity delta theta is greater than a predetermined value, is jetted and supplied into the cylinder which has been identified as being in a suction stroke by the second crank angle position signal and into a cylinder associated with the former and being in an e exhaust stroke. Thus the chance of the fuel increase correction by asynchronous injection is increased for the cylinders which are in a suction stroke and in an exhaust stroke.
