PROBLEM TO BE SOLVED: To control a continuously variable head lamp so as to be properly operated over a broad range of ambient light conditions. SOLUTION: This continuously variable head lamp has an effective illumination range by changing at least one parameter selected from a set including an aim horizontal direction, an aim vertical direction, and projected illumination. A system for automatically controlling the continuously variable head lamp mounted in a vehicle includes an imaging system which can determine the position of the lateral direction and height of a head lamp of an incoming vehicle and a tail lamp of an antecedent vehicle. This system further includes a control unit which can capture an image from the front face of the control vehicle. This image covers a glare area including a point where a driver in an incoming or antecedent vehicle perceives the head lamp and causes an excessive level of glare. When at least one vehicle is within the glare area, the illumination range of the head lamp is narrowed. COPYRIGHT: (C)2004,JPO&NCIPI