PURPOSE: To provide a temp. control method for an air conditioner which performs proximity control of an interior temp. with respect to a set temp.

CONSTITUTION: The arbitrary operation stage according to the set temp. in the temp. control of the air conditioner is set at least at ≥3 kinds. The set temp. and the error temp. in the interior temp. are detected 302. The calorific value over the entire part by a proportional integro-differential operation method with the calorific value for the prescribed error temp. detection time 305 in association with the detected temp. as a reference value and thereafter, the temp. is set 307 with the calorific value obtd. by regulating the detected calorific value with the calorific value of the previous state. The load of the system, for example, a fan motor, electronic pump, etc., are subjected to operation control in such a manner that the interior temp. is approximated to the set temp.