PURPOSE: To provide an existence detector capable of quickly discriminating the safety of a crew individually from a remote place when abnormality such as a fire or inundation, etc., occurs in a vessel.

CONSTITUTION: This device is equipped with a slave machine 4 which judges that abnormality for the safety of the crew H occurs and transmits it when posture abnormality due to the fall of a person at a prescribed angle from a perpendicularly standing state is detected, and also, the respiration abnormality of the person due to the stoppage of pressure fluctuation in the belt part of the waist by the respiration of the person or excess of a certain frequency is detected, a master machine 1 which receives a safety abnormality signal transmitted from the slave machine 4, and a centralized monitoring display device 6 connected to the master machine 1 and which monitors the safety of the person. Therefore, it is possible to quickly and precisely recognize the safety of all the crew H from a specific managing area E by automatically detecting the safety of the crew H and transmitting it to the remote place from the slave machine 4 when the abnormality occurs in the vessel, and to issue a command to deal with the abnormality, or to secure the safety of the crew H and to guide the crew.