PURPOSE: To enable the sensing of a vehicle regardless of the type thereof, by reflecting light emitted from a light emitter on a road surface to receive the reflected light with a receiver.

CONSTITUTION: Light 4 emitted from a light emitter 1 is reflected on a road 3 to be incident into a light receiver 2. When a vehicle runs on the road 3, the light 4 is intercepted by the vehicle and hence, the presence of the vehicle is sensed. Here, as the light 4 is projected slantly, the light beam is surely intercepted regardless of the height of the vehicle when the vehicle passes. Thus, a vehicle can be sensed regardless of the type thereof.