PURPOSE: To obtain excellent water-tightness in a nail hole by installing a ring on a part of a nail, which ring is made of elastic resin having specified hardness.

CONSTITUTION: A nail provided with a ring on its leading end is driven into a roofing member, for instance, which ring is made of elastic resin having hardness of 40 or more. Then the ring, not entering the nail hole, presses the member from an upper side. Only the nail enters the roofing member and a sheathing plate. The ring, made of elastic resin, is brought into close contact with the nail without a gap. In accordance with the driving of the nail, the ring presses the nail hole from the upper side, so that the gap between the nail and the member is perfectly sealed. As the roofing member, sheet of high water-proof performance, such as asphalt roofing, nonwaven fabric, film may be adopted. As the elastic resin, any material may be selected from natural rubber, synthetic rubber such as styrene rubber, urethane rubber, silicon rubber, and plastic rubber such as polyvinyl chliride, polyethyrene.