Theft detection mechanism and anti-theft device for vehicle

摘要

A theft detection mechanism is provided with a top ring which is depressed when a foreign object other than a key is inserted into a key inserting hole. A sensor is provided for detecting that the top ring is depressed. A top ring is inevitably pushed down when a foreign object other than a key is inserted into a key inserting hole to activate the sensor, thereby reliably detecting a stealing action. Moreover, the structure of a theft detection mechanism is made simple to reduce the cost thereof.