An illumination apparatus has a light source unit that can form a light distribution pattern by applying light into a virtual region, and an illuminance controller that can change the illuminance of at least a part of the light distribution pattern. The illuminance controller reduces the illuminance of the light distribution pattern in a region positioned in a first center in the vertical direction and a second center in a lateral direction, depending on a signal transmitted from an oncoming vehicle detector that transmits a signal according to the presence of an oncoming vehicle.