An ADB lamp unit (10) of a vehicle headlight includes a light source comprising a plurality of semiconductor light-emitting elements that can be turned on/off individually, and a reflector (16) having a reflective surface that is based on a paraboloid of revolution. The reflector (16) comprises a plurality of partial reflectors (16a to 16e) that are divided in the vertical direction, and the reflective surfaces of the partial reflectors are constituted such that the horizontal spread on a predetermined projection surface of light reflected by each partial reflector is approximately equal.
