National Sanatorium Oku Komyo-en (国立療養所邑久光明園) was opened on Nagashima Island in 1938 in order to re-admit the former inmates of Sotojima Hoyo-in Sanatorium, a public sanatorium opened in 1909 in the coastal reclaimed land in the Osaka bay area. In September 1934 the Sotojima Hoyo-in sanatorium was badly hit by a typhoon, which swept away the buildings and killed 187 people (173 inmates).

Oku Komyo-en had 1,174 inpatients in 1943. As of December 31, 2015, it had 123 residents with an average age of 84.8.

In order to open the sanatorium for integration with outside citizens and also to sustain the current level of services to leprosy affected residents, a geriatric nursing home has been opened on Oku Komyo-en’s premises.