A biometric information processing apparatus includes: a biometric information acquiring unit which generates a biometric image representing biometric information of a plurality of fingers of a user; and a processor adapted to extract a biometric region capturing biometric information of each of the plurality of fingers in the biometric image; obtain the first distance between the biometric regions corresponding to two adjacent fingers of the plurality of fingers; and estimate an angle of spread between the two adjacent fingers according to a ratio of a value obtained by subtracting a distance between bases of the two fingers from the first distance, to a length from a base of one of the two adjacent fingers to the biometric information.