To provide a method of completely preventing loosening and dropping of screws by vibration and the like during operation, in a device fastened with screws.

This locking ring with sealed instant adhesive is inserted in a manner of putting a washer, and then the screw is fastened, so that a doughnut ring-shaped tube is broken; the sealed instant adhesive is attached to the fastening portion of the screw; and the screw can be adhered and fixed instantaneously, simultaneously with the fastening of the screw. Thus, the loosening and dropping of the screw caused by vibration and the like will be completely eliminated.