An authentication apparatus, comprising: a storage part that stores a piece of authentication information in which a piece of terminal information that identifies a wearable terminal is registered, a communication part that makes communication with the wearable terminal to acquire the piece of terminal information, and an authenticating part that, in the case where the same piece of terminal information as the piece of terminal information registered in the piece of authentication information has been acquired by the communication part, performs user authentication, characterized in that the authentication apparatus further comprises: a wearing location identifying part that identifies a wearing location of the wearable terminal on the user's body, wherein, in the piece of authentication information, a piece of wearing location information that indicates the wearing location of the wearable terminal on the user's body is registered together with the piece of terminal information, the authenticating part performs user authentication in the case where the piece of terminal information that has been acquired is registered in the piece of authentication information and the wearing location that has been identified by the wearing location identifying part coincides with the piece of wearing location information. a storage part that stores a piece of authentication information in which a piece of terminal information that identifies a wearable terminal is registered, a communication part that makes communication with the wearable terminal to acquire the piece of terminal information, and an authenticating part that, in the case where the same piece of terminal information as the piece of terminal information registered in the piece of authentication information has been acquired by the communication part, performs user authentication, characterized in that the authentication apparatus further comprises: a wearing location identifying part that identifies a wearing location of the wearable terminal on the user's body, wherein, in the piece of authentication information, a piece of wearing location information that indicates the wearing location of the wearable terminal on the user's body is registered together with the piece of terminal information, the authenticating part performs user authentication in the case where the piece of terminal information that has been acquired is registered in the piece of authentication information and the wearing location that has been identified by the wearing location identifying part coincides with the piece of wearing location information. a wearing location identifying part that identifies a wearing location of the wearable terminal on the user's body, wherein, in the piece of authentication information, a piece of wearing location information that indicates the wearing location of the wearable terminal on the user's body is registered together with the piece of terminal information, the authenticating part performs user authentication in the case where the piece of terminal information that has been acquired is registered in the piece of authentication information and the wearing location that has been identified by the wearing location identifying part coincides with the piece of wearing location information.