To provide an accumulator fuel injection device for an internal combustion engine with a smaller size and lower cost electromagnetic actuator for actuating a needle valve, avoiding a reduction in the output of the engine, an increase in the exhaust amount of black smoke or an increase in the exhaust amount of NOx (nitrogen oxide) with the degraded control accuracy of a fuel injection amount by improving the control accuracy of the fuel injection amount in all lifting region of the needle valve for a fuel injection valve.

The fuel injection device for the internal combustion engine comprises a control groove engraved in the outer periphery of the needle valve for communicating an operating oil inlet portion with a pilot oil chamber or shutting it off with the displacement of a pilot valve. The control groove of the needle valve varies the area of an operating oil flow path between the operating oil inlet portion and the pilot oil chamber with the lifting operation of the needle valve.