Ōgaki Castle (Ōgaki-jō) is a castle located in the city of Ōgaki, Gifu Prefecture, Japan. Other names for the castle include Bi Castle (Bi-jō) and Kyoroku Castle (Kyoroku-jō). When the castle was originally built, it had four levels and four different kinds of moats. In the late 16th century, however, Toyotomi Hideyoshi realized the strategic location of the castle and further strengthened it by building the donjon.
Due to the historical importance of the castle, including its role in the Battle of Sekigahara in 1600, the donjon was designated a National Treasure in 1936. In 1945, the keep and the rest of the castle was destroyed during air raids in World War II; it was rebuilt in 1959. The current castle is a replica of the keep and the inside serves as a museum to artifacts from the Battle of Sekigahara in 1600.