Sub headlight unit and sub headlight system for use in vehicle that leans into turns, vehicle that leans into turns and method for controlling such sub headlight unit

A sub headlight unit (13L,13R) for use in a vehicle (10) that leans into turns, the sub headlight unit (13L,13R) including a plurality of sub headlight light sources (13La-c,13Ra-c) that illuminate, at the same side (e.g. left) as the side (left) to which the vehicle (10) is leaning, an area ahead and outward of the vehicle (10) with respect to a width direction of the vehicle (10). The plurality of sub headlight light sources (13La-c,13Ra-c) are arranged such that, under a state where the vehicle (10) is upright, each of them is positioned at the side (right) opposite to the side (left) to which the vehicle (10) is leaning. The plurality of sub headlight light sources (13La-c,13Ra-c) are configured to be turned on in accordance with different lean angles of the vehicle (10). The sub headlight light source (13Lc,13Rc) configured to be turned on upon a large lean angle of the vehicle (10) is located lower and outer at the side (right) opposite to the side (left) to which the vehicle (10) is leaning with respect to the width direction of the vehicle (10) than the sub headlight light source (13La,13Ra) configured to be turned on upon a small lean angle of the vehicle (10).