An authentication device comprising: an image acquisition unit configured to acquire a plurality of images with regard to a certain living body; an extraction unit configured to extract first biometric information from each of the plurality of images; an alignment unit configured to perform alignment between the plurality of images, based on the first biometric information; a calculation unit configured to calculate a coefficient based on feature of the certain living body, the feature being identified by a result of the alignment; a normalization unit configured to generate a normalized image by normalizing at least one image from among the plurality of images based on the coefficient; a registration unit configured to register second biometric information and the coefficient into a storage unit, the second biometric information being extracted from the normalized image by the extraction unit; characterized in that when a request for an authentication including another image is received: the normalization unit is configured to generate another normalized image by normalizing the another image based on the coefficient stored in the storage unit, the extraction unit is configured to extract third biometric information from the normalized another image; the authentication device further comprising: a comparing unit configured to compare the second biometric information to the third biometric information; and a determination unit configured to determine whether the authentication is succeed or not based on a result of a comparison by the comparing unit. an image acquisition unit configured to acquire a plurality of images with regard to a certain living body; an extraction unit configured to extract first biometric information from each of the plurality of images; an alignment unit configured to perform alignment between the plurality of images, based on the first biometric information; a calculation unit configured to calculate a coefficient based on feature of the certain living body, the feature being identified by a result of the alignment; a normalization unit configured to generate a normalized image by normalizing at least one image from among the plurality of images based on the coefficient; a registration unit configured to register second biometric information and the coefficient into a storage unit, the second biometric information being extracted from the normalized image by the extraction unit; characterized in that when a request for an authentication including another image is received: the normalization unit is configured to generate another normalized image by normalizing the another image based on the coefficient stored in the storage unit, the extraction unit is configured to extract third biometric information from the normalized another image; the authentication device further comprising: a comparing unit configured to compare the second biometric information to the third biometric information; and a determination unit configured to determine whether the authentication is succeed or not based on a result of a comparison by the comparing unit. the normalization unit is configured to generate another normalized image by normalizing the another image based on the coefficient stored in the storage unit, the extraction unit is configured to extract third biometric information from the normalized another image; the authentication device further comprising: a comparing unit configured to compare the second biometric information to the third biometric information; and a determination unit configured to determine whether the authentication is succeed or not based on a result of a comparison by the comparing unit. a comparing unit configured to compare the second biometric information to the third biometric information; and a determination unit configured to determine whether the authentication is succeed or not based on a result of a comparison by the comparing unit.