Futagoiwa rock is the debris flow deposits of Kunisaki Andesite erupted about 1.5 million years ago and became the shape like a human head due to the wave erosion. It is known to local people as the "Kishi Nobusuke" Rock, taking the name of a former prime minister of Japan. At the nearby seashore, fossils of mammals such as elephants and deer of 1.6 - 1.4 million years ago (Tsubami vertegrate fossil assemblage) were found.
* During the period of high-tide, you can observe this only from the distance.