Kosugi (小杉町; -machi) was a town located in Imizu District, Toyama, Japan.
On November 1, 2005 Kosugi was merged with the towns of Daimon and Ōshima, the village of Shimo, all from Imizu District, and the old city of Shinminato, to form the new city of Imizu and no longer exists as an independent municipality.
As of 2003, the town had an estimated population of 32,770 and a density of 795.00 persons per km². The total area was 41.22 km².