A method of certifying a user is provided. The method includes: generating a learning system; if a reference image is registered, analyzing the reference image by using the learning system to detect characteristic information; storing the detected characteristic information; photographing a user to acquire a user image; analyzing the user image by using the learning system to detect face characteristic information and additional information of the user; and comparing the face characteristic information and the additional information with stored characteristic information to certify the user. Therefore, a user certification is accurately performed.