In this paper, the author attemped to clarify the social characteristics of rural communities in Hokkaido by using the empirical data of ownership and utilization of common lands, which are important as the material basis of rural communities in Japan. The area selected for study was the settlement of Saruba in Biratori Town, Hokkaido, where common land (Saruba-kyodoyama) has been used effectively. As a result of investigation, it has been clarified that Saruba-kyodoyama has the same fundamental characteristics as common lands in Japanese traditional communities, such as formal equality of right in the community. However, there are some important differences. In case of traditional communities in Japan, the ownership of common land has been recognized as a certification of membership in the community. On the other hand, ownership is recognized only economically as money in Saruba-kyodoyama. Frequent movements of ownership shares in Saruba-kyodoyama resulted from those features of common land in Hokkaido. Differences in the ownership and utilization of common land in Hokkaido as compared to traditional communities in Japan illustrate the differences in social characteristics between rural communities in Hokkaido and those in the rest of Japan. Therefore the author considers that analyses of characteristics of rural communities in Hokkaido with the common lands used as indices has achieved a specific effectiveness.