To provide a biometric authentication program which improves success rate in identification, and simultaneously reduces false accept rate.

The biometric authentication program identifies a person by comparing biological information read through a biometric sensor with biological information which is stored in advance in a predetermined storage device. A computer operates as: a biological information extraction means for reading the biological information using the biometric sensor; a comparison means for comparing the read biological information with the biological information stored in advance to calculate similarity; an addition means for accumulating the similarity as accumulated similarity; a determination means for determining whether or not the accumulated similarity exceeds a predetermined threshold, to identify the person when the accumulated similarity exceeds the threshold and not to identify the person when the accumulated similarity does not exceed the threshold; and a collation threshold changing means for changing the threshold according to the number of biological information used for the accumulation by the addition means.