To provide authentication technology which can surely and easily provide a user with a predetermined service related to settlement while maintaining predetermined security, and can regulate by surely preventing the abuse of the service by a person other than a legitimate user.

An authentication apparatus 10, having an information communication function for enabling connection to a network, is provided with an authentication information input means 11 for inputting authentication information, a function card 3 which has a memory and a processing execution means, can perform predetermined processing, and stores master information for processing by comparing it with inputted authentication information, and an authentication means 12 which authenticates based on the master information included in the function card 3 and authentication information inputted from the authentication information input means 11, and outputs permission information when the both pieces of information have matched and the authentication is determined.