To provide a fastener capable of simply connecting an unit form for concrete and a form to each other.

This fastener is provided with a connecting plate for forming a U-shaped clamping member, both clamping plates, the bases of which are fixed to both sides of the connecting plate, and a connecting shaft mounted on the head plate extended from one of both clamping plates. The connecting shaft is inserted in a connecting hole of a connecting fin of the unit form, and the connecting fin is held by the clamping member.