To enable a nail to be hammered strongly in a risen state so as to retain the top of a nail claw between a main head and a sub head after the hammering by forming the main head and the sub head along its stem as a double-head nail.

The double-head nail 1 has a main head 2a formed at the end of a stem 3 and a sub head 2b formed spaced at an interval L from the main head 2a. When a timber M1 is joined to a timber M2 with a double-head nail 1, even though the main head 2a is hammered strongly, the sub head 2b abuts against the timber M1 to work as a stopper, so that the nail 1 cannot be driven moreover. The sub head 2b thrusts into the timber M1 to secure the joining force between the timbers M1, M2, and also, to become a state in which the main head 2a rises from the surface of the timber M1 spaced at a small interval L for retaining the top end 6a of a nail claw 6. in a framing completion ceremony or the like, when a common joist, a column, and a ridge pole, etc., are temporarily attached with braces, the main head 2a is not thrust into the timber, so that the top end of the nail claw is easily abutted to the main head to be able to perform a nail extracting work without damaging to the timber when the braces are detached after the framing completion ceremony.