To provide a control method for stopping overheat of the fan motor in an air conditioner surely and transmitting an alarm signal externally at a low cost.

An fan motor output signal from a microcomputer 1 and a CT current are ANDed (logical sum) (step S7). A decision is then made whether a specified value set in the microcomputer 1 (fan motor output set value) and the CT current fall within the range of normal value or not (step S8). If both values fall within the range of normal value, the control skips to step S11 before ending the processing. If the value of the CT current deviates from the range of normal value, a CT voltage is compared with a initial voltage set in the microcomputer 1 and temporary operation of the fan motor 11 is started if a failure is predicted (steps S9-S10).