To provide a chamfer strip for attachment to a concrete formwork, which allows a nail to be easily driven or withdrawn without damaging the chamfer strip and the nail to be removed for secondhand use.

A chamfer strip having a nail hole is provided with an approximately triangular prism shaped body 2 of resin such as plastic comprising: a cavity part 3 for reducing the internal weight; and cylindrical inlet port projections 41 and 43 for guiding a nail 6 to a specified direction, and cylindrical outlet port projections 42 and 44 for leading the guided nail to an outlet port through the cavity part 3, or a nail hole 5; so that the nail can be driven into a concrete formwork without being deformed.