An optical device includes a first light source that emits first light, a second light source that emits second light, first and second polarizing beam splitters, a dichroic mirror, a quarter-wave plate that changes the polarization state of light that passes through, a hyperspectral camera, and a visible light camera. The first polarizing beam splitter, the quarter-wave plate, and the dichroic mirror are disposed in an optical path of the first light in stated order. The second polarizing beam splitter and the dichroic mirror are disposed in an optical path of the second light in stated order. The hyperspectral camera receives first specularly reflected light out of first reflected light. The visible light camera receives second diffused light out of second reflected light.