To provide a device which prevents theft of a vehicle equipped with battery and identifies the robbed vehicle from the outside even in its traveling.

A switching device 2 for switching a normal driving circuit 3 and a theft prevention circuit 4 from a battery 1 is connected to a plus terminal of the battery and a start detector 50 for detecting the driving condition of an engine and a blinking device 40 for sending an electric signal which is repeated by its detection signal are provided in the theft prevention circuit 4. The output, of the blinking device 40 is connected to, at least, one of a front light, a brake light, and an alarm buzzer. When the engine 13 is started with the switching device 2 switched and connected to the theft prevention circuit 4, the front light, the brake light, and alarm buzzer connected to the blinking device 40 are repeatedly actuated so as to prevent traveling as they are and, if traveling, it can be identified to be the robbed car.