PURPOSE: To permit a rapid correction to be made of the amount of refrigerant in an indoor unit in a continuous operation without using pressure sensor, even in the case of the starting and stopping thereof.

CONSTITUTION: Upon the starting and stopping of an indoor unit, a control device 13 of the infoor unit 2 in a continuous operation obtains the difference in temperature between the outlet and inlet of an indoor heat exchanger 11 from the values detected by temperature sensors 10 and 12 and, when this temperature difference is a predetermined value or more, it obtains the opening degree ratio of electronic expansion valves 9 and computes the opening degree thereof from a predetermined relational expression using this opening degree ratio, thereby controlling the air conditioning.