Abstract: An object of the present invention is to provide a fastener made compact on the whole and capable of producing a strong fastening strength. To attain the object according to the invention, there is provided a fastener for being fitted to a fastening member (B) while continually exerting a tightening torque to the fastening member (B) fixedly screwed onto a mounting base, comprising a torsion coil spring formed in a winding shape so as to be inserted in an axial direction of the fastening member (B) into the fastening member (B) and having a fixing end (13) to be fixed onto the mounting base (A), and a detachable stopper (2) for restraining the torsion coil spring (1) in a state of accumulating a tightening torque.

Abstract: A tightening device includes an energizing member for energizing a tightening member to be secured to a tightening object. The energizing member integrally has at its one end an engaging part to be engaged with the tightening member. A switching member is connected to the tightening member for switching over to the constraining or operating state of the energizing force imparted to the tightening member by the energizing member. The switching member initially tightly holds the engaging part of the energizing member and the other end portion thereof to constrain the energizing force and is then separated from the engaging part and the other end portion of the energizing member to activate the energizing force.