A laser range finder projects light while changing a direction in a horizontal direction at a predetermined angle with respect to a vertical direction to also receive reflected light of the light, and detects a direction and a distance in which the light is reflected from an obstacle or the like, according to a difference time between a time of light projection and a time of light reception. A normal direction of a flat plane forming a road surface is detected on the basis of a polarized image. The laser range finder projects light such that the light has a predetermined angle with respect to the vertical direction so as to be orthogonal to the normal direction of the flat plane forming the road surface. The laser range finder can be applied to in-vehicle systems.