To provide a tightening aggregate formed in strip by diagonally arranging tightening pieces in parallel to each other and connecting them to each other, the tightening pieces used therefor, and its manufacturing method.

A nail 30 used for a tightening piece driving tool is provided with shanks 60 having head parts 70 provided on the longitudinal axis and a first end part, and a tip part 80 provided on the side opposite to the first end part. A tip part 90 is formed on the tip part 80 by converging first, second and third surfaces, and at least one surface of first and second surfaces 92,93 is converged from first and second side surfaces 62,63 of the shank 60 and forms an edge 96 of the prescribed acute angle relating to the axis in the longitudinal direction of the shank.