To accurately and speedily perform recognition processing of a proper vehicle user to improve the security property against theft of a vehicle, suppress cost, and extend and add a function easily.

A Bluetooth interface part 4 forms a radio link with a cellular phone 5 in which Bluetooth address is stored. The Bluetooth address stored in the cellular phone 5 owned by the proper vehicle user each is registered in a storage circuit 3 in advance. A control circuit 2 performs the connection operation of the radio link with the cellular phone 5 through the Bluetooth interface part 4 while an ignition switch 6 is on and the retrieval operation of the Bluetooth address stored in the cellular phone 5, outputs an alarm signal if it cannot retrieve the Bluetooth address registered in the storage circuit 3 to operate a horn drive circuit 11, and inhibits the start of an engine by an engine ECU(electronic control unit) 12.