PURPOSE: To alleviate the danger of a rear-end-collision by suggesting the possibility of braking to a following car earlier than the deceleration for braking of a preceding car begins thereby arousing attention.

CONSTITUTION: The accelerator pedal (2) of an automobile is equipped with a switch which senses the stepping force of the accelerator pedal (2). In the condition that the accelerator pedal (2) is stepped, the brake warning light (L2), which is provided at the position where it can be checked from the following car, is extinguished by switch control, and in the condition that the foot is detached from the accelerator pedal (2) as the preaction of applying the brakes, the brake warning light (L2) is lighted.