To provide a measuring bar used to set the height of a slab when concrete is placed which is simply operated and manufacturable at low cost.

This measuring bar for determining a slab which is a surface set by detecting the placement thickness of concrete includes a lower measuring bar which is buried in the placed concrete while being vertically installed on a base level, an upper measuring bar which is screwed into and connected to the upper end of the lower measuring bar through a washer larger in diameter than the lower measuring bar and the upper end of which projects upward from the slab, and a flexible pipe which is placed on the washer and into which the upper measuring bar is inserted while projecting from at least the slab.