In an air conditioner according to the present invention, an indoor unit includes an indoor air temperature detection unit to detect an indoor air temperature, a floor/wall/ceiling temperature detection unit to detect a floor and wall temperature and a ceiling ambient temperature, and a control device including a microcomputer in which a program relating to control of the air conditioner is embedded, wherein, in heating operation or ventilation operation, the control device performs circulator operation of moving air accumulating near a ceiling to a floor when the ceiling ambient temperature detected by the floor/wall/ceiling temperature detection unit becomes higher, by a predetermined threshold value or more, than an indoor air preset temperature set by a user.