Device and method for adjusting view range of vehicular monitoring device

A device for adjusting a view range of a vehicular monitoring device includes an overtaking pre-motion detector outputting an adjusting signal when an overtaking operation is predicted; and a controller in communication with the overtaking pre-motion detector and the vehicular monitoring device, controlling the vehicular monitoring device to move in response to the adjusting signal. The device may further output a warning signal to sound the horn or twinkle the vehicle lamp when the overtaking operation is predicted for safety consideration.