Disclosed is an air conditioner with spatial recognition and detection functions for deciding room shape by determining, based on temperature difference information between the floor and walls occurring during air conditioning operation, a human body detection position log, and a capacity zone of the air conditioner. In an embodiment, an infrared sensor detects a temperature of an area of the room by scanning the area and a control unit acquires thermal image data of the area scanned by the infrared sensor and then calculates a temperature of a wall of the room from the acquired thermal image data. The control unit detects a human body in the room from the thermal image data, calculates a distance between the body and the wall, and calculates a radiation temperature from the wall for the body based on the calculated temperature of the wall and the distance between the body and the wall.