To authenticate the person in question prior to purchasing the commodity employing a credit card through the use of a portable telecommunications terminal and enhance safety and workability concerned in a series of a value for settlements.

In an account settlement system containing a store 12, a PHS terminal 11 possessed by a purchaser buying the commodity under the credit card at the store 12, a telecommunications undertaker 15 of the PHS terminal 11 and a consumer credit company 13 entering into a member's store agreement with the store 12, the store 12 informs the consumer credit company 13 of the card information and the amount of the commodity prior to the buyer purchasing under the card. The consumer credit company 13 notifies from the card information the telecommunications undertaker 15 of the purchaser information together with the amount of the commodity. The telecommunications undertaker 15 transfers the notified details to the PHS terminal 11. The telecommunications undertaker 15 receives a personal identification number from the PHS terminal 11 as the response, which is transferred to the consumer credit company 13. Thus the consumer credit company 13 approves the store 12 to purchase the commodity due to the fact that a personal identification number registered beforehand in correspondence to the card coincides with a transferred personal identification number. Then the consumer credit company 13 settles the account for the purchased commodity.