This lighthouse was built to guide the way along the sea route passing near Mihara, Hiroshima Prefecture. Okunoshima is a small island, just four kilometers around, out in the sea off Tadanoumi town in Hiroshima Prefecture. It was once a critical military base, and was used for poison gas production. The round lighthouse has a 3.8m base. It rises 5.1 meters high and is 3.1 meters across. The tower section is made of hewn granite blocks, and the cast iron cupola on top stands 2.4 meters high.