Tsunohazu Girder, Railway bridge in Shinjuku, Japan

The Tsunohazu Girder is a girder bridge and overpass in Shinjuku 3-chome, completed in April 1927, whose upper deck carries JR lines including the Yamanote and Chūō slow lines. Beneath it runs a passage on the former Ōme Kaidō, linking the east and west sides of Shinjuku Station; until 31 March 2013 it formed part of Tokyo Metropolitan Route 430.

The bridge was built in 1927 during a period of rapid infrastructure expansion across Tokyo. It was created to handle the growing transportation demands of an expanding metropolitan area.

The name Tsunohazu comes from the old place name of the area, Tsunohazu 1-chome, which was absorbed into Shinjuku 3-chome. The girder spans the former Ōme Kaidō, the road that linked Shinjuku Station's east and west sides; until 31 March 2013 this passage formed part of Tokyo Metropolitan Route 430, the Shinjuku Station Front Line.

The passage under the girder links Shinjuku Station's east and west sides and was part of Tokyo Route 430 until 31 March 2013. From the east exit it is a short walk; from the west exit about three minutes. The Omoide Yokocho alley and Kabukicho lie on either side.

The lower passage follows the old Ōme Kaidō and linked the east and west sides of Shinjuku Station; until 31 March 2013 it formed part of Tokyo Metropolitan Route 430. The name Tsunohazu comes from the former district name of the area, once Tsunohazu 1-chome.