Patent ID: 8552864

Claim:
An intrusion detection system in which a detection signal leaked from a transmitting leaking transmission path is received at a receiving leaking transmission path, and, based on a change in signal level of the received detection signal caused by the intrusion of an intruding object between the two transmission path, the intruding object is detected, in which, it is determined that the intruding object has intruded when, based on a table that stores a threshold for an amount of variation in a received electric wave for each of a plurality of detection target blocks established along the transmitting leaking transmission path and the receiving leaking transmission path, the amount of variation in the received electric wave exceeds the threshold, wherein by way of a reporting unit that issues a report to indicate the amount of variation in the received electric wave when intrusion occurred between the two transmission paths, and a remote controller that generates a signal which changes a threshold in the table through the receiving leaking transmission path, the threshold is adjusted properly for each of the blocks with the remote controller based on the report issued from the reporting unit to indicate the amount of variation in the received electric wave caused by a trial intrusion between the two transmission paths by a threshold setting operator.