PURPOSE: To maintain high pull-out proof stress for a long time in a comparatively long scope until a nail shaft is pulled out of lumber in which a nail is driven.

CONSTITUTION: A plurality of first spiral lines which are inclined so that rotating force acts on a nail shaft when a nail is pulled out at 45 degrees or less for an axial line P of a nail are formed on a head side of a shaft section. A second spiral line 5 which is inclined at an angle which forms right angles to the inclination of the first spiral lines is formed on a tip side of the shaft section in such a manner that it turns around outer peripheral of the shaft section once at least. Furthermore, the length of the first spiral line part is larger than the length of the second spiral line 5 part. An angle α for the axial line P on the tip side of the shaft section of a ridge of the second spiral line 5 is smaller than an angle β for the axial line P on the head side of the ridge of the second spiral line 5.