Abstract: A variable fuel injection system for internal combustion engines is disclosed. In the injection system, a first control unit controls electromotive force for the solenoid coil of a fuel injector, thus controlling the amount of fuel to be injected from the nozzle of the injector into the combustion chamber of an engine. A second control unit controls the amount of actuating oil for the first control unit in accordance with an engine load, thus allowing the first control unit to control the electromotive force for the solenoid coil according to the engine load. The system controllably feeds fuel into the combustion chamber of an engine according to an engine load, thus conserving fuel with the amount of harmful exhaust gas being reduced.