In an engine including an in-cylinder injector and an intake manifold injector, the fuel injection ratio between the injectors with respect to a total fuel injection quantity in the homogeneous combustion operation is normally set in accordance with the engine operation state (engine speed, load factor). Upon transition from the stratified charge combustion operation to the homogeneous combustion operation, the fuel injection ratio is modified from that of the normal operation during a prescribed control period so that the fuel injection quantity from the intake manifold injector is increased than in the normal operation state, considering that the fuel newly injected via the in-cylinder injector immediately after transition of operation mode is likely to deposit inside the combustion chamber because of the fuel deposited therein during the stratified charge combustion operation. This prevents combustion deterioration in the engine upon transition of the operation mode.