The Tōzai Line (東西線, Tōzai-sen) is a rubber-tyred metro line located in Sapporo, Hokkaido, Japan.

It is part of the Sapporo Municipal Subway system.

Its name literally means "East-West Line", and it runs from Miyanosawa Station in Nishi-ku to Shin-Sapporo Station in Atsubetsu-ku.

The Tōzai Line color on maps is orange, and its stations carry the letter "T" followed by a number.