PURPOSE: To prolong the service life of a protective apparatus by interrupting conduction of a compressor when the temperature difference of an indoor heat exchanger at the time of starting conduction of the compressor and after elapsing a first specified time is lower than a specified level and resuming conduction of the compressor upon elapsing a second specified time.

CONSTITUTION: A temperature detector 13 detects the temperature of an indoor heat exchanger 5 in an indoor unit. A microcomputer 12 compares the temperatures of the heat exchanger 5 at the time of starting conduction of a compressor and after elapsing a first specified time. When the temperature difference is lower than a specified level, conduction of the compressor 1 is interrupted until a second specified time elapses. Even if the compressor 1 is locked and a self-reset overload relay 30 functions periodically, the number of functioning times thereof is minimized thus enhancing the service life of the overload relay 30 and thereby the reliability of protective operation.