To simply prevent malfunctions, such as in drop revolution or engine stall, even when generating several times of pulse breakage caused by the contamination of a rotation angle pulse with noise in a control device for the fuel injection amount of a diesel engine having an electrically controllable spill valve.

There is provided an electronic control device, having a calculation means for calculating the pulse times TS1, TS2 and TS3 of three pulses in the vicinity of a spill valve opening time among the rotation angle pulses outputted by a rotation angle sensor, a means for calculating the next opening time of the spill valve based on the above calculation, a judgment means for judging the possibility of pulse breakage in a rotating angle pulse (NE pulse) based on the deviation of discrete value of a pulse counter at completion of one cycle, and a correction means for calculating the corrected values by multiplying a sound pulse time TS1 instead of TS2 and TS3 shortened with pulse breakage by the prescribed correction coefficients RTOTS2 and 3, when it is judged that the pulse breakage has occurred.