To prevent the crack of a pile when a surveying nail is driven into the top surface of pile driven into a surveying point in advance by forming the diameter of the surveying nail into a value in a specified range.

The shaft diameter B of a surveying nail 1 is formed in about 1.5-3mm, and the head diameter C is 2.5-4 times as the shaft diameter B. And a cross groove 3 is cut in the top surface of a head part 1b of the surveying nail 1. The intersection point of the cross groove 3 is position on about central part of the head part 1b, and width A of the cross groove 3 is about 1mm. And the cross groove 3 is a V type groove, and the intersection point of a groove bottom 3a of the cross groove 3 becomes a reference point P at surveying. And multiple spiral-shaped grooves 2 are cut into a shaft part 1a in the axis direction. The groove 2 is provided so that the holding power of the surveying nail 1, driven into a wooden or plastic pile driven into a surveying paint in advance, for a pile, is improved. Since the diameter of the shaft part 1a of the surveying nail 1 is made small in this manner, the pile is not cracked with the surveying nail 1.