PURPOSE: To determine a predetermined position of a dashpot angle precisely when controlling an actuator of a vehicle.

CONSTITUTION: A target value is formed for driving an actuator 50 by a control circuit 28 and an adaptive unit 30. The target value is inputted to a control unit 42 and a drive signal is obtained based on the difference between the target value and an actual value with respect to the position of the actuator. The target value of the actuator position is fixed in dependence on operating parameters 20, 22 of a vehicle or an engine at least at the idling state so as to obtain a target idle speed. On the other hand, during a non-idling state, the target value is formed based on the target value obtained with respect to idling so as to achieve the desired position of the actuator.