To provide a method/device for authentication for preventing complete faking by rejecting data inputted for authentication though the third party tries to illegally obtain and use data inputted by a normal user for authentication and to provide a program.

The device has a registered data storage part 13 for storing registered data prepared based on the physical features of the user, a registered data collation part 11 which collates authentication data obtained by reading the physical feature of the user in the case of receiving the authentication request of the user with the registered data, a previous data storage part 14 for storing previous authentication data authenticated in the case of the previous authentication request, a previous data collation part 12 for collating the inputted authentication data with the previous authentication data, and a judging means 15 for authenticating the data when the collating result of the part 11 is coincident and the collating result of the part 12 is not coincident to the authentication request of the user.