A head light system for a vehicle using a discharge lamp provides low beam mode and high beam mode, together with glare stop structure. The head light system comprises a discharge lamp (4) mounted on a base plate (1), a shade (7) for selectively and partially shading light source (5) of said discharge lamp (4), and a moving means (K) for sliding said shade (7) relative to said discharge lamp (4) along an arrow (X) in longitudinal direction of said discharge lamp (4). Said shade (7) has a leg (7b) which penetrates said base plate (1), and said leg (7b) is coupled with an iron piece (9) in a solenoid (8) which is fixed to a rod (6) fixed under said base plate (1). Said iron piece (9) is urged by a spring (10) so that shade plane (7a) of the shade (7) covers partially the light source (5) of the discharge lamp (4) when said solenoid is not energized so that low beam mode is provided. When said solenoid (8) is energized and pulls said iron piece (9) against the spring (10), said shade (7) slides so that said light source (5) is free from the shade plane (7a) to provide high beam mode.