To facilitate the safekeeping and distribution management of a card and also to keep security high by validating the password number and the amount of a prepaid card available in an internet at the time when the card owner makes a purchase at a store, etc.

At an electronic account settlement center (a) where a prepaid card is available, a prepaid card having its password number is sold to a purchaser (c) at a convenience store (b). A password number of 10 to 16 digits and an amount are validated when the purchaser (c) paid his charge and then the card information is read at a POS terminal of the store (b). This validity is notified to the center (a) via a main office calculation center (bb) of the store (b). When the purchaser (c) purchases a commodity from a virtual store (d) via an internet, he uses his password number for the payment. At the center (a), the validity is checked for the password number and the amount via the store (d) and a charge amount is settled for the store (d). Then the approval of this settlement is notified to the purchaser (c), and the store (d) confirms the settlement of charge and forwards the commodity to the purchaser (c).