 It became Tomioka Town within Kitakanra District, Gunma Prefecture on April 1, 1889 with the creation of the municipalities system after the Meiji Restoration.In 1950 Kitakanra District was renamed Kanra District.On April 1, 1954, Tomioka annexed the neighboring town of Ichinomiya, and the villages of Ono, Kuroiwa, Takase, and Nukabe, and was raised to city status on November 1, 1958.