Abstract: A pulsed light emitting element emits pulsed light that is linearly polarized in a first polarization direction, the pulsed light passes through a polarizing beam splitter and a lens in this order and is radiated onto a target object, reflected light passes through the lens and the polarizing beam splitter in this order, is linearly polarized in a second polarization direction that is different from the first polarization direction, and is concentrated on a light receiving element, the pulsed light emitting element and the light receiving element are provided on a focal plane of the lens, and the optical axis of the pulsed light and the optical axis of the reflected light overlap.