PURPOSE: To restrict the electric power consumption of a remote controller without widening the fluctuation width of temperature by a method wherein the time interval of emission of an infrared rays emitting device is controlled in accordance with a difference between a set temperature and a present temperature as well as the change in temperature difference.

CONSTITUTION: An infrared-ray emitting interval control unit 8 controls a variable time interval generating unit 9 to change the time interval of emission of infrared rays. In case the temperature difference is large, a control commanding unit 4 generates a command to operate an air-conditioner in the maximum capacity and the infrared rays are not emitted until the temperature difference and the changing amount of temperature difference are reduced. In case the capacity of the air-conditioning device is controlled properly and a temperature is stabilized near the set temperature or the change of temperature difference between the present temperature and the set temperature is small, the time interval of emission of infrared rays is lengthed. A function to change the time interval of output of control command of infrared rays in accordance with a difference between detecting and set temperatures and the changing amount of temperature difference is provided in such manner, whereby the electric power consumption of the infrared rays emitting unit, which is the most of the consumption in the remote controller, may be restricted without enlarging the fluctuating width of temperature and the life of dry cells or the like can be elongated.