A biometric information processing apparatus, comprising: a biometric sensor configured to acquire an image of a palm and a fingerprint image for each of a first finger, a second finger and a third finger of a user; a quality determination unit configured to determine, for each of the first finger, the second finger and the third finger, a quality score of the fingerprint image based on directional flow of ridges included in the fingerprint image; an authentication feature extraction unit configured to extract authentication features used for matching from the fingerprint image for each of the first finger, the second finger and the third finger; a normalization unit configured to normalize relative positions between the fingerprint images of the first finger, the second finger and the third finger by using the image of the palm; and a relative feature extraction unit configured to extract relative features from the fingerprint image normalized by the normalization unit for each of the first finger, the second finger and the third finger, wherein the relative features for a particular finger are the coordinate values of minutiae points of the fingers other than the particular finger with respect to the position of the center of the fingerprint of the particular finger; a positional alignment reference position calculation unit configured to determine a reference position for a positional alignment process, using the relative features of the fingerprint image of a finger which the quality score is a given value or more; and a matching processing unit configured to perform the positional alignment process to align the position of authentication features registered in a database with the extracted authentication features using the determined reference position, and to authenticate the user by calculating, for each finger, a matching score with respect to the extracted authentication features and the registered authentication features after positional alignment. a biometric sensor configured to acquire an image of a palm and a fingerprint image for each of a first finger, a second finger and a third finger of a user; a quality determination unit configured to determine, for each of the first finger, the second finger and the third finger, a quality score of the fingerprint image based on directional flow of ridges included in the fingerprint image; an authentication feature extraction unit configured to extract authentication features used for matching from the fingerprint image for each of the first finger, the second finger and the third finger; a normalization unit configured to normalize relative positions between the fingerprint images of the first finger, the second finger and the third finger by using the image of the palm; and a relative feature extraction unit configured to extract relative features from the fingerprint image normalized by the normalization unit for each of the first finger, the second finger and the third finger, wherein the relative features for a particular finger are the coordinate values of minutiae points of the fingers other than the particular finger with respect to the position of the center of the fingerprint of the particular finger; a positional alignment reference position calculation unit configured to determine a reference position for a positional alignment process, using the relative features of the fingerprint image of a finger which the quality score is a given value or more; and a matching processing unit configured to perform the positional alignment process to align the position of authentication features registered in a database with the extracted authentication features using the determined reference position, and to authenticate the user by calculating, for each finger, a matching score with respect to the extracted authentication features and the registered authentication features after positional alignment.