To inhibit deterioration of properties of exhaust gas even in high load operation of FFV.

In the fuel control system for an engine 10 comprising a port injection valve 15a for injecting gasoline to an intake port 12 and a cylinder injection valve 15b for injecting alcohol-mixed gasoline to a combustion chamber 10a and adjusting the injection from each injection valve 15a, 15b according to the operating condition, if the required injection amount is equal or more than a predetermined value in high load operation, the injection amount from the cylinder injection valve 15b is set to the maximum injection amount in the range the properties of exhaust gas is not deteriorated, and the part of the injection amount not to fill the required injection amount is made to be injected by the port injection valve 15a.