PURPOSE: To perform stable opening and closing operation of a valve and also to reduce noise generation by magnetizing a solenoid quickly at the start of supplying a steady state magnetizing current through utilizing counter electromotive force energy induced in the solenoid due to break of an initial magnetizing current.

CONSTITUTION: A magnetization compensating circuit C is made of a booster coil S1 and a switching circuit SW. The booster coil S1 stores the counter electromotive force energy produced in a solenoid S during the stopped period of the drive of a first switching element Q1. The switching circuit SW is driven by the energy stored in the booster coil S1 at the start of driving a second switching element Q2, and feeds an initial magnetizing current ia, which exceeds a steady state magnetizing current ib, into the solenoid S temporarily. Thus, the counter electromotive force is utilized effectively, and stable driving of the solenoid S is performed at the start of supply of the steady state magnetizing current ib, and in addition, since the counter electromotive force is absorbed and utilized by the booster coil S1, generation of noise is also reduced.