Most trains are all-station "Local" services, but some limited-stop "Rapid" express trains have operated in morning and evening hours. ; Local ; Express ; Limited Express
The first section of the line, from Komuro to Shin-Kamagaya, opened in March 1979, including a temporary connection to the Shin-Keisei Line at Kita-Hatsutomi. As other tracks were connected, it changed name to "Hokusō Kōdan Line" in April 1987. Over 17 years later, the railway properties of the HDC corporation transferred to Chiba New Town Railway, on July 1, 2004, and the whole line was renamed as the Hokusō Line.
Western section
This section was planned as a railway access to Chiba New Town. Initially proposed by a committee of the then Ministry of Transport, the route was numbered "Line 1", as the northern extension of Tokyo Metropolitan Bureau of TransportationLine 1 to Komuro area of Chiba New Town. In 1979 the first phase of this section between and opened. The through-operation via Shin-Keisei Line to began, on a temporary basis until the second phase of this section could connect the town directly to the Keisei and Asakusa Line network. The second phase section to on the Keisei Main Line opened in 1991, and through-operation began. In the following year, Shin-Keisei included Shin-Kamagaya Station as a transfer station, and abandoned the temporary route.
Eastern section
The section east of Komuro was initially the eastern part of a once-planned Chiba Prefectural Railway as an extension of Line 10. The line was to be built from via to parallel to the line above, then to terminate at present. The first section between Komuro and was opened in 1984, and the operations were commissioned to the present Hokusō Railway.
March 9, 1979: Hokusō Line of Hokusō Development Railway –. Through-operation via Shin-Keisei Line to on temporary basis.
April 1, 1987: On the section of Komuro – Chiba New Town Chūō, Hokusō Development Railway became the Category-2 Railway Business operator, while HUDC became Category-3 Railway Business. On the commencement of the Railway Business Act, Act No. 92 of 1986) for the privatization of the Japan National Railways. Simultaneously, the entire stretch was renamed to Hokusō Kōdan Line
July 4, 1992: Shin-Keisei opened Shin-Kamagaya Station. Through-operation to Shin-Keisei terminated. The section of Kita-Hatsutomi – Shin-Kamagaya was abandoned.
April 1, 1995: Chiba New Town Chūō – Inzai-Makinohara, as Hokusō Cat-2, HUDC Cat-3
After the abandonment of the planned Narita Shinkansen, routes of rapid transit to Narita Airport had long been discussed. For a utilization of partially completed tracks of the Shinkansen, JR East and Keisei lines to were realized. A much faster line had long been needed, and for that purpose the first priority was the Keisei – Hokusō route. In 2001, a new Cat-3 entity, Narita Rapid Rail Access commenced building a new line connecting Inba-Nihon-Idai to the junction to Narita Airport Rapid Railway which is a Cat-3 company of existing access railways, the tracks of the formerly planned Narita Shinkansen. The express trains are operated by Keisei as a Cat-2 operator with maximum speed at, the fastest in Japanese private railway together with Hokuetsu Express, which enables a 34-minute journey from to Narita Airport. The line opened in July 2010.
Local subsidies
Hokuso Railway fares are significantly higher than those of other private railways in the region. A journey of 12.7 km on the Hokuso Line costs 540 yen, while a 23.8 km journey costs 720 yen. Equivalent journeys on the Keisei Main Line cost 250 yen and 360 yen respectively; equivalent journeys on JR cost 210 yen and 380 yen respectively. The difference in fares is largely due to the debt burden remaining from the portion of the line built and owned by Hokuso Railway itself; this is also the case for the Tōyō Rapid Railway Line and the Saitama Rapid Railway Line, which are also known for having comparatively high fares. In 2009, Chiba Prefecture and several municipalities along the line agreed with Hokuso Railway for an average fare reduction of 4.6%, in exchange for which they agreed to subsidize half of the estimated revenue loss of 600 million yen. The fare reduction was implemented in July 2010 at the time of the opening of the Narita Sky Access Line. In 2011 and 2012, the cities of Shiroi and Inzai elected new mayors on platforms of negotiating for further fare reductions and stopping public subsidies respectively; a third-party study commissioned by the two city governments concluded in August 2013 that the Hokusō Line would break at even more discounted fare levels without local subsidies. Hokuso, on the other hand, has argued that increased consumption tax rates and capital expenditures related to upgrading the Pasmo system will force them to raise fares in 2015.
Incidents
On June 11, 2020, the seventh car on a 7300 series set derailed upon arriving at Aoto Station. According to witnesses, the pantograph on the derailed car had detached from the train and became entangled with the overhead wire.
