The secondary headlight unit that vehicle uses and secondary headlamp system and vehicle

The present invention provides a kind of suppression to maximize and have secondary headlight unit that adapt to the illumination range in diversified traveling place, carry out the vehicle use turned with inclination attitude.A kind of secondary headlight unit carrying out the vehicle use turned with inclination attitude, above-mentioned secondary headlight unit has the overall width direction foreign side of the above-mentioned vehicle in the side to overall width direction and front carries out the multiple secondary headlight beam of illumination, the brightness of above-mentioned secondary headlight beam is changed corresponding to the inclination angle of above-mentioned vehicle, when the inclination angle of above-mentioned vehicle reaches the reference value individually set in each above-mentioned secondary headlight beam, above-mentioned secondary headlight beam becomes the brightness of regulation, the said reference value of above-mentioned secondary headlight beam is the biggest, on the overall width direction of above-mentioned vehicle, the lateral border of the illumination range of the regulation illumination of above-mentioned secondary headlight beam when overlooking viewing is located foreign side.