1. A person recognition apparatus having an authentication data input unit which acquires authentication data, and a dictionary storage which stores dictionary data for authentication, said person recognition apparatus authenticating a person to be authenticated on the basis of authentication data acquired from the person by said authentication data input unit and the dictionary data stored in said dictionary storage, comprising: a dictionary formation unit which forms new dictionary data for authentication on the basis of authentication data acquired by said authentication data input unit; an authenticator which, after the dictionary data is formed by said dictionary formation unit, reacquires authentication data by said authentication data input unit, and collates the reacquired authentication data from said authentication data input unit with the dictionary data formed by said dictionary formation unit; and a dictionary updating unit which, in a case where the collation by said authenticator is successful, updates the dictionary data by using the authentication data acquired by said authentication data input unit after the dictionary data is formed by said dictionary formation unit.