An electrically-controlled throttle valve apparatus includes a motor, a speed reducing mechanism for reducing the rotation speed that is transmitted from the motor, a throttle valve connected to the speed reducing mechanism, and a force applying arrangement for applying force to the throttle valve in the direction of returning the valve to its initial position and for adjusting the opening of the throttle valve by driving the motor. Specification parameters of the motor, the speed reducing mechanism, and the force applying arrangement have values such that the operation time t from the minimum opening to the maximum opening of the throttle valve, which is determined by an evaluation equation obtained from equations of motion of the throttle valve, is less than a prescribed target operation time t* of the throttle valve. Furthermore, the resistance and the induction voltage constant of the motor are determined so as to satisfy a constraint equation obtained based on Ohm's law.