To exactly indicate a brake state of own vehicle regardless of a road condition or a travelling environment.

On the basis of information form a road surface sensor 6, a navigation 7, and a distance between vehicles sensor 8, when it is derived that a road surface is easy to slip, when it is derived that a vehicle travels on a downward slope, and when it is derived that relative speed with a preceding vehicle is increased, the lighting width of a high mount strap lamp is increased, and a brake state is exactly indicated according to the state having a possibility of a danger, regardless of the state traveling on the easy-to-slip road surface, a state traveling on the downward slope, and the state rapidly approaching the preceding vehicle.