Kazusa (加津佐町 Kazusa-machi) was a town located in Minamitakaki District, Nagasaki, Japan.
On March 31, 2006 Kazusa was merged with the towns of Arie, Fukae, Futsu, Kitaarima, Kuchinotsu, Minamiarima and Nishiarie, all from Minamitakaki District, to form the new city of Minamishimabara.
As of 2003, the town had an estimated population of 7,870 and a density of 322.81 persons per km². The total area was 24.38 km².