A method of authentication capable of avoiding an easy copying of a module used for personal authentication of an IC card or the like and thereby raising the reliability of the personal authentication, comprising having an electronic circuit having a hardware configuration corresponding to a predetermined authentication processing provided in an IC of an IC card carry out authentication processing using a PIN and data generated at an authentication apparatus at random and having the authentication apparatus similarly carry out the authentication processing, compare the processing result received from the IC card and the processing result obtained by itself, and, when they coincide, authenticating the user of the IC card as the legitimate user.