In this study, chemical compositions were reexamined on the glass beads excavated from the Usu-Oyakotsu site in Date City, Hokkaido. As a result, it was possible to clarify that these glass beads are composed of potash lime glass and potash lead glass. In particular, it is noteworthy that the majority was potash lime glass. In addition, it became clear that the potash lime glass is divided into two compositional types, lead - containing type and lead - free type. Especially for lead - containing type, it might be one of the features of potash lime glass distributed in the early Ainu culture period.