In an air conditioner, one of a linkage mode or a non-linkage mode is selected by a user as a control mode of an external device. In the air conditioner, when the linkage mode is selected, on/off control of the external device by using a human detection sensor is permitted during operation, whereas on/off control of the external device by using the human detection sensor is inhibited during suspension of operation. In the air conditioner, when the non-linkage mode is selected, on/off control of the external device by using the human detection sensor is always permitted, irrespective of whether the air conditioner is in operation or not.