Provided is an authentication apparatus that performs user authentication, using a wearable terminal worn by a user, whereby allowing a high security to be achieved. It includes a storage part that stores a piece of authentication information in which a piece of terminal information that identifies the wearable terminal worn by the user is registered, a communication part that makes communication with the wearable terminal worn by the user to acquire a piece of terminal information, and an authenticating part that performs user authentication in the case where the same piece of terminal information as that registered in the authentication information has been acquired by the communication part.