Annaka (安中市 Annaka-shi) is a city located in Gunma Prefecture, Japan. The city was founded on November 1, 1958.
As of March 31, 2011, the city has an estimated population of 63,584, with 23,575 households and a population density of 230.09 persons per km². The total area is 276.34 km².
On March 18, 2006, the town of Matsuida (from Usui District), was merged into Annaka. Usui District was dissolved as a result of this merger.