Disclosed are a monitor subject monitoring apparatus, a monitor subject monitoring method, and a monitor subject monitoring system configured to determine a first body state of a subject, based on an image data of the subject, and to determine a second body state of the subject, based on physiological data of the subject, wherein the subject monitoring apparatus, the subject monitoring method and the subject monitoring system are operable, when it is determined that one of the first and second body states of the subject is not abnormal, to re-perform a corresponding one of the determinations, and then determine whether or not a notification indicating that the subject is in an abnormal state should be issued, based on a result of the re-performed determination about the one of the first and second body states.
