improved method and apparatus for injecting fuel for a diesel engine are disclosed which are constructed such that a push rod is disposed in a nozzle body and fuel is injected into a combustion chamber by actuating the push rod . the improvement of the invention consists in that push rod actuating force is accumulated for a certain period of time while the push rod is stationarily held by means of an electromagnetic coil which is energized . fuel injection is thus carried out by releasing the accumulated force by way of deenergization of the electro - magnetic coil . in an embodiment of the invention push rod actuating force is extracted from a cam driving mechanism and a coil spring disposed between the cam driving mechanism and the push rod serves as a push rod actuating force accumulating means . in a modified embodiment of the invention push rod actuating force is extracted from a combination of an auxiliary piston and a rocker arm and an auxiliary cylinder serves as a push rod actuating force accumulating means . preferably , an auxiliary electromagnetic coil is disposed on the nozzle body so as to assist in actuation of the push rod . in another modified embodiment of the invention similar to the preceding one a hydraulic system is provided between the auxiliary piston and the push rod as a push rod actuating force accumulating means .