To improve a security level without lowering authentication easiness in authentication processing using both a biological characteristic and a password.
The rate of coincidence is calculated by collating a 1st biological characteristic with registered biological characteristic information (101 to 105), when the rate of coincidence is equal to or more than a decision reference value, authentication is decided to be successful (106 to 107), the authentication is decided to be a failure in the other cases (106 to 108), the number of password input request digits is calculated by using the rate of coincidence calculated with the 1st biological characteristic in the case of the authentication failure, and a password input that is equal to or more than the number of the digits is requested (108 and 109), coincidence is confirmed by collating the inputted password with a registered password, when the coincidence is confirmed, the decision reference value is lowered (111 and 112), the rate of coincidence is calculated by collating a 2nd biological characteristic with the registered characteristic information (102 to 105), and when the rate of coincidence calculated on the basis of the 2nd biological characteristic is equal to or more than the changed decision reference value, the authentication is decided to be successful with the 2nd biological characteristic (106 to 107).
NISHIJIMA NAOHIRO
MATSUZAKI RUMIKO
WATANABE KAZUNARI
SHIMADA SHIGEO
IWASAKI TETSUYA
HIRATA KAZUTERU
