To prevent illicit use and to inexpensively provided a card which can be re-used by initializing and re-loading a counter when mutual authentication can precisely be executed with a card/writer terminal accessing to card.

A non-volatile semiconductor memory 1 consists of EEPROM and a counter re-charge key 15 and a user identification key 16 are stored in an area which cannot be read. S mutual authentication circuit 4 discriminated whether the card reader/writer terminal is genuine or not. When the terminal genuine, a signal showing that the card is true comes from a terminal-side and the content of a counter 11 becomes zero by a signal from a compactor 3, an AND circuit 5 adds a value to the counter 11 through a write circuit 2 by an instruction signal (addition pulse) from the terminal. When correct anthentication can be executed with the card reader/writer terminal, the counter 11 can be initialized or re-loaded and it can be re-used.