To provide a system and a method which can surely authenticate an individual who uses a credit card.

Portable telephone set data, a credit card number, and a credit card password number are supplied as card discrimination data to a portable telephone carrier computer system 21. Further, the card discrimination data are transferred from the portable telephone carrier computer system to a credit card company computer system 22 and registered as registered discrimination data. When a credit card is used, the credit card data, portable telephone set data, and credit card password code recorded on the credit card are transmitted from a terminal device 31 to the credit card company computer system. The credit card company computer system receives the data and compares the receive data with registered discrimination data and permits the terminal device to use the credit card when they match with each other.