To accurately calculate in a short time without increasing a communication load in the case of calculating a dissipation heat amount value of each indoor unit of an air conditioner.

The air conditioner charging system having an air conditioning outdoor unit 6 with a wattmeter 8, and a plurality of air conditioning indoor units 4 connected to the unit 6 comprises an information distributed-processing unit 10 for inputting, storing and integrated data of used electric energy of the unit 6 and data processing operating state data of the units 4 at a predetermined sampling period, and a central processing unit 1 for calculating an account based on the processed data of the unit 10. In this case, the unit 10 has a counter 11 for counting an actual air conditioning time of the units 4 in the sampling period. The unit 10 calculates to correct based on a counted value of the counter 11 in the case of calculating a mean dissipation heat amount in the period of each indoor unit 4.