PURPOSE: To accurately recognize a presence or absence state by recognizing and judging as absence when there is no lock signal inputted with a thumb turn and there is a lock signal with a cylinder.

CONSTITUTION: A control part 2A recognizes a locking/unlocking state according to the input of the lock signals inputted from an electronic lock 5 with the thumb turn and cylinder to judge the presence or absence state. Namely, when there is the lock signal inputted with the thumb turn, the presence is recognized and judged and when there is no lock signal with the thumb turn and there is the lock signal with the cylinder, the absence is recognized and judged. Presence/absence information is reported from a control part 2A to a centralized control board 4. Therefore, the presence or absence can be recognized with the lock signals of the thumb turn and cylinder of the electric lock 5 installed in an entrance door and the accurate recognition is enabled without any special operation. Further, when abnormal signals of various sensors are recognized in the presence state, the electronic lock 5 is immediately reset to make a 3rd person take measures quickly.