In this study, we applied nPVI to rhythm analysis. nPVI is an index proposed to quantify the difference between stress and syllable beats in linguistics and has recently been used for the comparative analysis of rhythms in Western music history. We digitized a total of 5,484 songs published in all nine volumes of “Nihon Min’yo Taikan” (Anthology of Japanese Folk Songs). The difference in the agogic contrasts was clarified with the folk songs from each region. In addition, we calculated the latitude and longitude of the place from where each song was recorded and created a database in a format that can be used for GIS. By converting the data into mesh sections and integrating the nPVI values, the difference in the rhythm leaps of each song in each region was visually clarified.