An illumination device includes a laser element, a fluorescent material, a light projection lens, a laser light reflector, a detection element, and a control unit connected to the detection element. The fluorescent material is disposed in a direction of propagation of laser light from the laser element, and converts the laser light into illumination light. The light projection lens and the laser light reflector are disposed in a direction of propagation of the illumination light from the fluorescent material. The detection element can detect the laser light reflected on the laser light reflector and external light. The control unit calculates a comparison value by comparing the amount detected by the detection element when the laser element is emitting the laser light and the amount detected by the detection element when the laser element is not emitting the laser light.