The Watarase Keikoku Line (わたらせ渓谷線, Watarase Keikoku-sen) is a Japanese railway line connecting Kiryū Station in Kiryū, Gunma and Matō Station in Nikkō, Tochigi.

The company and line are also known as Watakei (わた渓) or Watetsu (わ鐵).

As the name suggests, the line runs along the Watarase River through a deep valley.

The Ashio Railway Co. opened the line to Ashio-Motoyama (2 kilometres or 1.2 miles beyond Mato) in 1911–12[clarification needed] to service the Ashio Copper Mine, and leased the line to JNR in 1913.

Operation of the line between Kiryū and Matō was transferred to the Watarase Keikoku Railway, a third-sector company, in 1989.