PURPOSE: To completely, accurately and separately adjust only the power rate of an automatic vending machine by calculating the charge of the consumed power by an external instruction.

CONSTITUTION: A wattmeter 1 is connected to an automatic vending machine controller 2. When a block B1 is connected to the controller 2, a switch 4 that can be operated by only a power rate collector is pushed. Thus the controller 2 immediately calculates the power rate to be paid and gives a prescribed instruction to a coin mechanism 3 to pay an amount equal to the power rate. Meanwhile a card owned by only the power rate collector is put into a card reader/writer 5 when a block B2 is connected to the controller 2. Thus the controller 2 immediately calculates the power rate to be paid and gives a prescribed instruction to the reader/writer 5 to write the amount data corresponding to the power rate into a card. In addition, an automatic transfer operation can be carried out when a bank on-line system B3 is connected to the controller 2.