The N-S trending trough basins developed in the Ishikari-Teshio Belt, central Hokkaido, were infilled by Middle Miocene coarse clastic sediments. According to former studies, the coarse clastics have been estimated to be derived from the northern part of Esashi-Hidaka Belt that was uplifted in relation to the collision events of the Amurian and Okhotsk Plates.In Hobetsu area located at the southern part of the Ishikari-Teshio Belt, the Kawabata Formation consists of turbidites and associated coarse clastics, and overlies the mudstone of the Takinoue Formation. The Kawabata Formation is characterized by monotonous alternating beds of sandstone and mudstone, and intercalated non-channelized, sheet-like coarse clastic deposits. Horizontally, coarsening eastward pattern is observed, but there are few facies changes along the basin axis. The facies and facies distribution pattern suggest that the Kawabata Formation was deposited in basin plain environment and coarse clastics were derived from the eastern hinterland through a slope area which developed at the basin margin.In addition, we recognized metamorphic rock fragments and detrital garnets derived from high grade metamorphic rocks (e.g. granulitic rocks originated from muddy sediments) in some sandstone of the Kawabata Formation. This fact suggests the Kamuikotan "tectonic" and Hidaka Metamorphic Belts, which are situated to the east of the Hobetsu area, are the most probable provenance.Although former studies regarded the northern part of the Esashi-Hidaka Belt as a provenance area of the Kawabata Formation, this study proposes the coexistence of the eastern hinterland located in the southern part of Esashi-Hidaka Belt which had been thought to be sea area during Middle Miocene time. It also suggests the earlier timing of uplifting of the Hidaka metamorphic rocks than the former studies.