To detect a space area where a person is present in a room, so as to control load equipment in accordance with the position of the person in the room.

A sensor device S includes in the body: an infrared array sensor 21 monitoring the temperature distribution in the room; a sensor circuit 22 detecting the position where the person is present in the room based on the temperature distribution in the room, detected by the infrared array sensor 21; and a wireless communication module 23 imparting information on the position where the person is present in the room to an electric power meter by communicating with an electric power meter. The infrared array sensor 21 includes: a sensor element with thermal infrared elements arranged in a matrix shape; and a light receiving optical system disposed in front of a light receiving surface of the sensor element.