In a method of regulating optical axes of headlights for an automotive vehicle so that a light intensity boundary of low beam of headlights lies within a predetermined range displayed on a monitor TV, light intensity boundary points are detected along vertical lines arranged at predetermined picture element intervals in the horizontal direction; the detected boundary points are connected to determine a light intensity boundary line composed of horizontal and inclined lines; and the optical axes of the headlights are so regulated that the determined light intensity boundary line lies within the predetermined range on the monitor TV, thus enabling the headlight regulating work to be effected automatically for each vehicle at high speed and high reliability.