Konagai (小長井町 Konagai-chō) was a town located in Kitatakaki District, Nagasaki, Japan.
As of 2003, the town had an estimated population of 6,437 and a density of 208.12 persons per km². The total area was 30.93 km².
On March 1, 2005 Konagai, along with the town of Tarami, from Nishisonogi District, and the towns of Iimori, Moriyama and Takaki, all from Kitatakaki District, was merged into the expanded city of Isahaya.