To provide a safety detector capable of accurately determining abnormality with easy system construction by determining the presence of an inhabitant in a room and detecting motion while distinguishing a small animal from the inhabitant.

A contact output device comprises a transmitter which processes signal output from a sensor 12 installed in the living room to detect the action of at least the inhabitant, and has a transmitting section 14 for transmitting a count value; a holder 8 mounted to an article carried with the inhabitant and including a transmitter transmitting radio wave in a predetermined cycle; and a receiver which receives signals from the transmitter and radio wave transmitted from the holder, and has an action determining section for determining the abnormality of the object person from the count value, a radio wave receiving determining section for determining the absence of the inhabitant from the presence/absence of signals from the transmitter and radio wave transmitted from the holder, and a contact output section for outputting a contact signal based on the determined result of two determining sections. A longitudinal face with a sensor face of a casing of the transmitter is provided with inclination for making a detection range of the sensor more than level.