To make the safety of an old man living alone by himself easily and surely confirmable.

A safety confirming device is constituted in such a way that, when a light receiving sensor 10 does not again detect an optical signal L generated from a remote controller 3 for a television receiver 2 within a safety confirming period of time after the sensor 10 detects the signal L, the confirming device can transmit a life confirmation requiring signal SG from a terminal 20 for confirming safety to a host computer through a telephone line 30. In addition, the sensor 10 detects individual optical signals generated from each optical signal transmitters 15 in accordance with IDs in an interlocking way with various kinds of safety confirming sensors and, when the individual optical signals are detected, a terminal 20 for life confirming transmits a life confirming signal including ID to the host computer 41 through the telephone line 30.