PURPOSE: To prevent an entire stop of power supply due to overcurrent by a method wherein, when a overcurrent signal or the like is received, a plurality of air conditioners are interrupted in a preset priority order, and when a temperature signal from a temperature detecting part after the interruption reaches a set value or more of temperature changing amount, the air conditioner is restarted.

CONSTITUTION: A main power source circuit S is branched and connected to a plurality of air conditioners A1 to A5 through branch breakers B1 to B5 together with various load means. In this case, it is determined that a overcurrent signal read in from a overcurrent detecting part 2 exceeds an allowance current value, an operation signal of each air conditioner is read in from a monitor 4, an air conditioner of the highest proiority of interruption is selected, and the air conditioner is stoppted by a control part 6. Then, if it is found that the level of the overcurrent signal remains high, an air conditioner of the highest but one priority of interruption is stopped. In addition, a temprerature signal of a room whose air conditioner is stopped is taken in from the temperature detecting part 3, and if a changing amount of the room temperature is larger than a set value, the air conditioner is restarted.