According to one embodiment, an authentication method includes performing a verification process includes extracting a face region from an image input from a camera photographing a person, reading first facial characteristic data from the extracted face region, and reading second facial characteristic data associated with personal identification data representing the specific person corresponding to the detected first facial characteristic data, acquiring hand-shape transition pattern data showing transition of a hand shape and associated with the personal identification data associated with the second facial characteristic data, extracting a hand region from the image input from the camera, detecting a transition of a hand shape from the extracted hand region, and determining whether the hand-shape transition pattern data represents the detected transition of the hand shape.