To set starting current to regulated hold current or more when current-carrying is carried out to an electromagnetic coil of an electromagnetic driving valve, and current is converted from initial starting current into a regulated hold current at fully closing or fully opening position.

When a valve is closing operated, in the case where a lift sensor output exceeds a trigger level V1, a valve closing electromagnetic coil is turned on, and thereby, coil current rises. When the lift sensor output exceeds a trigger level V2, the valve closing electromagnetic coil is turned off. When the lift sensor outlet exceeds a trigger level V3, the valve closing electromagnetic coil is turned on again, and simultaneously clocking is started by a timer circuit 44. When the lift sensor output exceeds a trigger level V4, valve speed slows down. If already the clocking by the timer circuit 44 is completed, control is transferred to hold current control by a PWM signal. If valve speed is fast and the the clocking by the timer circuit 44 is not completed, starting of coil current is continued so as to obtain absorbing force which is necessary for holding the valve, and control is firstly transferred to hold current control when the clocking is completed.