PURPOSE: To restore and intensify the corrosion resistance of metal forming nails by forming the nails having shanks and heads from carbon steel wire coated with a corrosion resistant metallic layer for protection and coating at least the heads with a polymer layer for protection.

CONSTITUTION: The carbon steel wire coated with the corrosion resistant metallic layer for protection, for example, a zinc layer is prepared. Each roof nail 14 formed by a nail producing machine has the head 16 and the shank 18 having a pointed end. When the head 16 of the roof nail 14 is formed, material of a substantial amount is shifted in a transverse direction in such a manner that the steel existing under the region 22 is exposed in this region, by which a 'window' 22 partially lacking the protection from the corrosion is formed. The nail is coated by the polymer layer for protection protecting the head 16 so as to cover the window part 22 of the head of the nail where this metallic layer is interrupted, by which the corrosion resistance of the nail is restored. As a result, the corrosion resistance of the metal forming the nail is restored and intensified and this restoration and intensification are efficiently achieved when the nail is used for a fluid pressure actuation type automatic nailing machine.