PURPOSE: To automatically set a shared section to a warning state by detecting the warning and non-warning state of a monitoring section and deciding whether the other monitoring sections are to be set in the warning state or non-warning state.
CONSTITUTION: A private section 2A has been in a warning state. When the user of a private section 2B operates a password card for a card reader 5B at the time of returning home, the private section 2B becomes the warning state. Then all the private sections 2A and 2B are in the warning state and a shared section 3 is set to the warning state to monitor an intrusion by judging that there is no one in the building. When a person coming out of the private section 2B operates the password card for the card reader 4, the warning state of the shared section 3 is released. In this case, the warning state of the private section 2 is not released so that the shared section 3 becomes the warning state again. Then, when the user of the private section 2A operates the card reader 4 at an entrance 1 in the next morning, the shared section 3 becomes the non-warning state and the user makes the private section 2A non-warning state. Thus, the warning state of the shared section 3 remains released.
