Arao, city, northwestern Kumamoto ken (prefecture), west-central Kyushu, Japan. It faces Ariake Bay, about 20 miles (32 km) northwest of Kumamoto city.
Arao was a poor village until the opening of the Miike coal mine and the arrival of a major railway in the early 20th century. A military munitions factory was established in 1940. After World War II, however, the mine and the factory closed. Arao is now a residential suburb of Ōmuta, just to the north. Pop. (2005) 55,960; (2010) 55,321.