PURPOSE: To stop leakage of a refrigerant when leakage of a refrigerant occurs by detecting whether leakage of a refrigerant during cooling occurs or not.

CONSTITUTION: A motor-operated expansion valve control device for an air- conditioner comprises indoor piping temperature sensors 7a-7g which detect a piping temperature and are arranged at the respective piping of indoor units 3a-3g, an electronic control unit 9 to compute and process signals from the indoor piping temperature sensors 7a-7g, an expansion valve control means 10 to receive a signal from the electronic control unit 9 and control the openings of motor-operated expansion valves 6a-6g, a compressor control means 11 to control the frequency of a compressor 4, and a trouble diagnosing control unit 12 to effect control of trouble diagnosis.