VEHICLE ROBBERY PREVENTION METHOD AND DEVICE

This invention provides a theft prevention method and device for a vehicle in which before a battery voltage falls to the extent that releasing of a theft prevention system is impossible, the battery voltage is read and a warning is issued of a drop in the battery voltage so that a user is allowed to take measures such as replacement or charging of the battery and the system can be released without trouble for the start of the engine at the time of driving. A theft prevention method for a vehicle, allowing that a main switch 5 connected to a battery 6 is turned on to actuate theft prevention means 8, 9, 10 and operation of the theft prevention means is stopped through releasing operation, wherein a battery voltage is read immediately after the main switch 5 is turned on, it is determined whether or not the battery voltage is no larger than a given value after the releasing operation, and a warning is issued if the battery voltage is no larger than the given value.