A fuel injection valve drive control device includes a boost circuit having a boost coil, a switching component (FFT or the like) supplying a switching current from a battery source voltage to the boost coil, and a boost capacitor accumulating a boosted voltage generated by the operation of the switching component; a discharge circuit for discharging the accumulated electric charge via a current limiter (e.g. discharge resistor, constant current source) and a discharge switch (FET or the like); and a monitoring circuit for monitoring the accumulated voltage. The discharge circuit is caused to operate when the control device is shutting down and performs a deterioration/failure diagnosis of the boost capacitor and an operation check of the discharge circuit on the basis of a monitored voltage value of the boost capacitor at starting the discharge operation and a monitored voltage value of the boost capacitor after a predetermined time has elapsed.