Apparatus for controlling throttle valve of internal combustion engine

An apparatus for controlling an opening degree of a throttle valve of an internal combustion engine using a DC motor, in which a real opening degree of the throttle valve is detected, a target opening degree of the throttle valve is set in accordance with an operation state of the internal combustion engine, an output voltage of a DC power source is boosted, and one voltage of the boosted voltage and the output voltage of the DC power source is selected in accordance with an opening degree difference between the real opening degree and the target opening degree to apply the selected one voltage to the DC motor.