The present invention relates to a headlight for automobile, with rectangular front opening, of the type comprising a reflector in the axis of which are disposed a light source for dipped-beam illumination cooperating with cut-off means, and a light source for far-beam illumination, a horizontal upper side and a horizontal lower side intersecting the reflector to delimit the rectangular opening of the headlight, wherein the upper side is substantially closer to the optical axis than the lower side, with the result that, for a total, unchanged height of the headlight, the zone of the mirror furnishing the dipped-beam illumination is reduced, this allowing an optimum compromise for far-beam and dipped-beam illumination.