To provide a nail which does not break the back face of a plate-like building material which becomes a backing when mounting thin plate-like roof tiles or wall material, and improves the pull-out strength.

In a nail which has a flat head part 2 at one end of a shank body 1 and a sharp tip part at the other end 3, a face near the tip part shall be a large wedge-like inclined face 4, and on its back face side is provided a recessed groove 5 and small inclined faces 6 and 6' so that the nail can be driven in a gentle S shape. As a result, the pressure against the axial extension line relative to the back ace of a building material is dispersed so that it is possible to prevent the breakage of the back face, to improve the strength, as well as to prevent the impairment of aesthetics.