A microcomputer is configured to: calculate, the drive period of a previous injection, an injection interval, and an uncorrected target drive period for a current injection; obtain a correction period by increasing an internal variable from zero in proportion to the drive period of the previous injection during this drive period, attenuating the internal variable at a first-order delay during the injection interval, dividing the internal variable by a coefficient of the proportion at a start time point of the present current supply, and setting a result of the division as the correction period; and set a period obtained by subtracting the correction period from the uncorrected target drive period as a current drive period, to thereby supply a signal indicating the current drive period to the injector via a driver.