This is a small Buddhist hall located at Cape Kannonzaki on Himeshima Island, in Higashi-Kunisaki County, Oita Pref. The object of worship is Bato (Horse-Head) Kannon. This hall is included in the Seven Wonders of Himeshima Island. The other six are Sakasa-yanagi (inverted willow tree), Kanetsuke-ishi Stone, Hyoshi-mizu (spring water), Ukita (quaking rice paddy), Amida-kaki (oysters in the shape of Amida) and Uki-su (the shrine that is never covered with water even at high tide). Sennin-do Hall with an area of 6.6 m2 has the legend that it affords enough space for 1,000 good people who are persecuted by debt collectors. The hall stands on the 40 m cliff facing the sea, where visitors can enjoy the view of the sun setting in the sea. The cliff is made of obsidian and it is very exceptional in Japan that the obsidian layer is exposed to open-air. Obsidian is a prefecturally designated Natural Treasure. Tools made of Himeshima obsidian have been excavated from ruins of Stone Age not only in Kyushu but also in Chugoku and Shikoku regions.