An illumination device for a vehicle, includes: a detection unit that detects a person; an illumination unit that illuminates light in a direction toward a road surface, an illumination region of the light being alterable; and a control unit that, in a case in which a person is detected by the detection unit and there is a possibility of collision between the detected person and the vehicle, controls the illumination unit so as to illuminate light at a region in a range of view of the detected person that is separated from the person by a pre-specified distance, and so as to move the light in a direction of movement of the detected person while maintaining the separation at the pre-specified distance.