Abstract: A control method and apparatus which detects a solenoid current as a voltage, and PWM-controls a transistor for a solenoid such that the detection voltage becomes a target voltage. A feedback gain, used for setting PWM signal output time, is set in accordance with the difference between the detection voltage and the target voltage such that the greater the difference becomes, the greater the feedback gain becomes. Further, a detection voltage after a predetermined period is estimated based on the change of detection voltage from the past. If the estimation value overshoots the target voltage, a difference B between the detection voltage and the target voltage and a difference C between the detection voltage and the estimation value are obtained, and the feedback gain is varied by multiplying the feedback gain by the ratio B/C between the these differences.