To make it possible to execute an electronic business transaction via the payment and the exchange of electronic currency which are simultaneously performed and to deal with many types of currency, by performing the exchange of currency simultaneously with the payment of the charge or a purchased commodity when the types of currency are different between a consumer and a store.

When the ordering information is sent to the automatic currency exchange/payment device 7 via a consumer terminal 4, the device 7 inquires about the type of currency. Then the electronic currency stored in an electronic purse 1 of the consumer is sent to an electronic currency exchange part 6 of a bank, and the exchange of currency is asked to the bank. Receiving the exchange request from the device 7, the part 6 converts an amount of money into the currency of another country and sends it to the device 7. Receiving the converted currency, the device 7 sends the electronic currency to a store terminal 5. The terminal 5 stores the received electronic currency in an electronic purse 2 of a store.