The present invention makes it possible to obtain good characteristics of forming sprays of fuel jetted through a plurality of injection ports of a fuel injection valve with respect to separation of sprays in different directions, atomization, jetting angles and penetrating force.Fuel jetted through the injection ports of the fuel injection valve is jetted in separate jets from a plurality of fuel flow separating holes of a sleeve nozzle. On the other hand, band-like assist air flows are jetted in a two-dimensional manner from slit-like air holes opened on the opposite sides of the fuel flow separating holes to impinge obliquely against the jetted fuel. Atomization of fuel jetted through the plurality of fuel flow separating holes is thereby promoted and fuel sprays are accurately separated and supplied independently in two directions toward two intake valves while the directions of jets from the injection ports of the fuel injection valve are maintained, thus injecting and supplying fuel. As a result, an amount of fuel impinging directly against walls which separates and forms two intake ports is reduced and an amount of atomized sprayed fuel directly entering a combustion chamber from the intake ports is therefore increased, thereby improving combustion characteristics.