Fuel injection control system for internal combustion engine and method

Control for injecting fuel is performed both through a first nozzle hole (4) and a second nozzle hole (5) by setting a needle valve (2) at a high-lift position in a fuel injector. The fuel injection is performed only through the first nozzle hole (4), not through the second nozzle hole (5) by setting the needle valve (2) at a low-lift position of the fuel injector. When operation of an internal combustion engine continues for a predetermined period of time under conditions requiring the needle valve (2) to be set in the low-lift position, control for injecting the fuel through the nozzle hole (5) is performed.