Behavior monitoring system and power saving method thereof

A behavior monitoring system for monitoring a behavior of a monitoring target person who lives in a residence, the behavior monitoring system comprising:

• a detection section including an opening/closing detection sensor provided on a door partitioning each room of the residence and configured to detect opening and closing of a corresponding door, and a human detection sensor provided in each room and configured to detect presence/absence of a human;
• a determination section configured to determine, based on detection of opening and closing of a door of any room of the residence by the corresponding opening/closing detection sensor and detection of a human by the human detection sensor provided in the room, that the monitoring target person is present in the room;
• and
• a power control section configured to switch, in a case where the determination section determines a room in which the monitoring target person is present, a mode of the detection section provided in a room other than the room in which the monitoring target person is present from a normal mode to a power saving mode.