Possible tsunami deposits were found at two archeological sites along the Pacific coast near Hamana Lake in central Japan. This region has frequently suffered heavy damage from large earthquakes along the Nankai trough. Three sand deposits covering layers that include archeological remains were found at one of the sites. The ages of the sand deposits were constrained by remains just below the sand deposits, which showed good correspondence to the ages of three major historic earthquakes that seriously damaged this area, i.e., A.D. 1707, 1605, and 1498. These features strongly suggest that the sand deposits were caused by tsunami from the historic earthquakes. Core samples obtained near this site showed that a similar sequence continues into a deeper part, suggesting the existence of tsunami deposits of events older than A.D. 1498, before which few historical records are available in the Tokaido side. Further investigation of tsunami deposits in this area would yield useful information on the reconstruction of large earthquakes along the Nankai trough.