1915: Fujiwara Tramway (藤原軌道株式会社,Fujiwara Kidō Kabushiki-gaisha?) was licensed to build a 762 mm (2 ft 6 in) gauge steam-hauled tramway. It was renamed Shimotsuke Tramway (下野軌道株式会社,Shimotsuke Kidō Kabushiki-gaisha?) in the same year.
2 January 1917: A 3.6-mile (5.8 km) section from Daiya-gawa Hokugan Station to Kinugawa Nangan Station was opened. The line was extended a further 2.5 miles (4.0 km) the same year.
March 1919: Ōhara Station to Shimotaki Station section was opened.
October 1919: Daiya Mukō Imaichi Station to Shin-Imaichi Station section was opened.
1 January 1920: Shimotaki Station to Fujiwara Station section was open to complete the whole 10.9-mile (17.5 km) line.
6 June 1921: The company name was renamed Shimotsuke Electric Railway Co., Ltd. (下野電気鉄道株式会社,Shimotsuke Denki Tetsudō Kabushiki-gaisha?).
9 March 1922: The whole line was electrified at 600 V DC.
April 1927: The corporate headquarters was relocated to the Tobu Railway headquarters in Tokyo.
22 October 1929: 1,067 mm (3 ft 6 in) gauge operation began on all the line.
1931: The voltage was raised to 1,500 V.
1 May 1943: Shimotsuke Electric Railway was bought out by Tobu Railway. The line became Tobu Kinugawa Line.
9 October 1986: Yagan Railway Aizu Kinugawa Line through service began.
12 October 1990: Aizu Railway Aizu Line through service to Aizu Tajima Station began.