1. An apparatus for analyzing a rhythm structure of a music audio data set, comprising: a beat position acquisition section adapted to acquire beat position information indicated of individual estimated beat positions of the music audio data set to be analyzed; a division section configured to divide the music audio data set into a plurality of possible pattern segments on the basis of the beat positions indicated by the beat position information acquired by said beat position acquisition section, said division section being configured to provide a plurality of sets of possible pattern segments by dividing the music audio data set in accordance with individual ones of a plurality of division models obtained by sequentially shilling a first beat position of the possible pattern segments; a reference performance pattern acquisition section adapted to acquire a plurality of reference performance patterns; a matching section configured to make comparison between individual ones of the possible pattern segments and individual ones of the reference performance patterns for each of the sets of possible pattern segments and, on the basis of the comparison, determine, for each of the possible pattern segments of the set, at least one reference performance pattern that matches the possible pattern segment; and a selection section configured to identify, on the basis of the at least one reference performance pattern determined by said matching section for each of the possible pattern segments, at least one combination of reference performance patterns, where one reference performance pattern is associated with each of the possible pattern segments, for each of the sets of possible pattern segments, and select one optimal combination from among the combinations identified for the sets of possible pattern segments.