1. A personal identification apparatus comprising: a storage device configured to store specific information of each of registered persons; an extraction device configured to extract specific information of an object person from the object person; a classification device configured to classify whether the object person is included in the registered persons by comparing the specific information of the registered persons, which is stored in said storage device, with the specific information of the object person, which is extracted by said extraction device; and a registered information operation device configured to sort an arrangement order of pieces of the specific information of the registered persons, which is stored in said storage device, in accordance with a use situation of the registered persons, or set whether the registered persons are to be subjected to classification.