PURPOSE: To easily prevent the burglar of an automobile during warming-up by connecting an engine circuit for a main switch starting an engine via a key and a starter motor circuit for an auxiliary switch starting the engine via a manual operation piece in parallel.

CONSTITUTION: A side brake 3 is applied to turn a side brake following switch 2b on during the worm-up operation. A manual operation piece 2a is rotated by one step to the IG position to turn an engine circuit A on, and the manual operation piece 2a is turned by one more step to the ST position. A starter motor circuit B is closed to start a starter motor 6, and an engine is cranked. The manual operation piece 2a is returned by one step to the IG position after the engine is started. If a person intending to steal an automobile releases the side brake 3 under this condition, the following switch 2b is turned off, and the engine is stopped. When a key 1a is inserted into a main switch 1 and turned, the engine circuit A is closed to allow the running of a vehicle.