PURPOSE: To make excellent the performance of an accelerating operation without making an air-fuel ratio overrich, by controlling the amount of non-synchronous injection appropriately, irrespective of the timing of start of the accelerating operation.

CONSTITUTION: When a fuel correction calculation routine SACC is started, first a throttle opening TA stored in RAM68 is fetched, and ΔTA, i.e. the amount of increase in the throttle opening is determined at a step 121. When ΔTA is above a determined acceleration value, an advance is made to a step 133, and when it is below said value, an advance is made to a step 132. (In this case, a demanded amount ASYTAU of non-synchronous injection is made to be zero.) At the step 133, ASYTA is determined from a table stored in ROM70. Next, ΔASYTAU is determined, and then whether it is positive or negative is decided. The non-synchronous injection of ΔASYTAU is performed when the value thereof is positive, but it is not performed when this value is negative. After the injection in an amount corresponding to the degree of acceleration is executed in this way, the non-synchronous injection is not conducted, and thus an air- fuel ratio does not turn overrich.