A preset waiting period is previously set on the basis of a signal in correspondence to a detection of a start point of a detection of a no-tooth portion of a signal rotor. In the case of a control for injecting a fuel after the preset waiting period has elapsed, an output of a signal indicating a start point of an actual detection of the no-tooth portion by a waveform shaping portion is delayed due to the existence of the no-tooth portion. A control computer corrects the preset waiting period to be shorter by an amount corresponding the delay. Accordingly, an accuracy of a fuel injection start timing control is improved.