It is located about 100 meters south of Komazuka Tumulus. The tumulus is a circular mound with the diameter of about 14 meters. It is said that Choshimaru who was taking care of the Prince Shotoku’s beloved horse “Kurokoma” was buried in this tumulus. From the excavation at the north side of the tumulus conducted in 2000, a head portion of earthen horse and harness were unearthed. The time of construction is unknown.