PURPOSE: To improve the operatability and the security by providing an identification number input unit with a communicating means with a poratable medium, and making a terminal unit only transmit the result for confirming the correctness of the identification number input unit.

CONSTITUTION: An identification number input unit 2 transmits an identification number stored in a second identification number storing means 6 to a terminal unit 1 by an identification number outputs means 7. A collating means 5 in the terminal unit 1 collates the transmitted identification number with an identification number stored in a first identification number storing means 4, the terminal unit 1 acknowledges the correctness of the identification number input unit when the result of collation is 'correct', and the control is transferred to the next process. On the other hand, when the result of collation is 'incorrect', the terminal unit 1 regards the unit 2 as faked, and terminates the process. After the confirmation of the correctness, an IC card 3 is inserted into the unit 2, then the number is input by an user from an identification number input means 8. A collation command output means 9 transmits the identification number collating command with the inputted identification number as the data to the IC card 3 through the communicating means 16, 17.