To effectively prevent a phenomenon in which the secrecy of a password is lost even when the execution of a transaction processing necessitating an ID recording medium and a password is left to a third person.

The owner of an IC card can register an arbitrary second password by using a telephone line 29 for a host computer 15. This second password is invalidated when a preliminarily set valid period passes, or when a certificate issuing processing using the pertinent second password is operated more than the preliminarily set upper limit number of times. In a state in which the second password is registered in the host computer 15, an automatic certificate issuing machine 2 permits the issuing processing of a certificate when individual identification information read from the ID card inserted into a card reader 3 and a password inputted from a touch panel 7 provided on the surface of a CRT display 6 match the combined data of individual identification information and the second password registered in the host computer 15.