Kokubu Castle (国分城, Kokubu-jō) also called Maizuru Castle is the remains of a castle structure in Kirishima, Kagoshima Prefecture, Japan. The site is called a Kokubu castle, but it is a fortified residence rather than a castle.

In 1604, Shimazu Yoshihiro built the castle and moved from Tomiguma Castle. Shimazu Yoshihisa lived a retired life in the castle, he died January 21 in 1611

Currently Kokubu elementary school is on site, but stone walls, moats and gates still remain.