Headlight device and leaning vehicle including headlight device

A headlight device for use in a leaning vehicle including a vehicle body that leans in a left direction when turning in the left direction and leans in a right direction when turning in the right direction, the headlight device comprising:

• a headlight configured to emit light frontward of the leaning vehicle to form:
• a lower light beam,
• an upper central light beam above the lower light beam in an upward-downward direction,
• an upper left light beam farther in the left direction than the upper central light beam, and
• an upper right light beam farther in the right direction than the upper central light beam;
• and
• a control device that controls light emission from the headlight such that the light emission from the headlight changes without any operation made by a rider of the leaning vehicle, by
• forming both the upper left light beam and the upper right light beam while the leaning vehicle is traveling straight, and reducing a brightness of the upper left light beam and a brightness of the upper right light beam, responsive to an oncoming vehicle or a preceding vehicle, or both, being illuminated by the upper left light beam and by the upper right light beam, respectively,
• forming the upper left light beam while the leaning vehicle is turning in the left direction, and maintaining the brightness of the formed upper left light beam regardless of whether the oncoming vehicle or the preceding vehicle, or both, are illuminated by the formed upper left light beam, and
• forming the upper right light beam while the leaning vehicle is turning in the right direction, and maintaining the brightness of the formed upper right light beam regardless of whether the oncoming vehicle or the preceding vehicle, or both, are illuminated by the formed upper right light beam.