<p>The coasts of the Japan Trench and the Kuril Trench have been repeatedly damaged by tsunamis in the past. In the 17th century, the 1611 Keicho-Oshu earthquake, the 1677 Aomori-Oki earthquake, the 17th century great earthquake (Tokachi-OKi and Nemuro-Oki) occurred, as well as a tsunami caused by the 1640 Hokkaido Komagatake eruption. Tsunami deposits of these earthquakes have been identified over a wide area along the coast from Hokkaido to the Tohoku region. In previous studies, tsunami deposits from the 17th century great earthquake and the 1611 Keicho-Oshu earthquake have been identified along the eastern Pacific coast of Hokkaido and along the Pacific coast of Tohoku region, respectively. The 1640 Komagatake eruption tsunami left the 17th century tsunami deposits in Uchiura Bay. On the other hand, tsunami deposits in the central part of the Iburi Coast to the northern part of the Hidaka Coast may have been deposited by any of the 1640 Komagatake eruption, the 17th century great earthquake, the 1611 Keicho-Oshu earthquake, or other earthquakes, which have not been identified at present. The purpose of this study is to estimate the source of tsunami that reconstructs the 17th century tsunami deposits from the northern Hidaka coast to Uchiura Bay in Hokkaido, because it is important for future earthquake and tsunami disaster prevention to clarify the origin of the tsunami deposits with unknown sources. First, tsunami heights estimated from historical records, distribution of tsunami deposits, characteristics of coastal tsunami arrival, and tsunami history estimated from geologic records are summarized. Next, tsunami simulations were conducted for the 17th century great earthquake, the 1611 Keicho-Oshu earthquake, the Aomori-Oki earthquake, Hokkaido (2012) model, Cabinet Office (2020) model, and the 1640 Komagatake eruption, and tsunami sources that reproduce (1) the distribution of tsunami deposits, (2) the reproducibility of tsunami arrival characteristics, and (3) tsunami history were examined. Finally, the possibility of (1) a large slip (18 m to 40 m) in Aomori-Oki and (2) coupling of the Tokachi-Nemuro-Oki and Aomori-OKi, as assumed by the Hokkaido (2012), Cabinet Office (2020) and Sato et al. (2022) models, are discussed based on seismological findings, tectonic background of the Japan Trench and the Kuril Trench, and examples of M 9-class great earthquakes occurring in Japan and abroad. As a result, the most reasonable source of the 17th century tsunami deposits distributed from the northern Hidaka coast to the Uchiura Bay is the tsunami caused by the 1640 Komagatake eruption. The results of this tsunami simulations indicate that the height of the tsunami deposits in some areas is considerably higher than that of the previously identified tsunami deposits, and that further detailed investigations are necessary.</p>