PURPOSE: To confirm that a special high-strength bolt is screw-fitted in a base material by applying constant torque when a nut is fastened by screw-fitting the bolt in the base material from the joining member side.

CONSTITUTION: The method is constituted in such a way that in a condition of gripping a screw-fitting pin tail 14 of a special high-strength bolt 1 having a fastening pin tail 13 and the screw-fitting pin tail 14, a base material 4 side screw part 11 is screw-fitted in a base material 4 so as to continue to one screw part 12 sandwiching a cylinder part 10 between them, and a rupture groove 16 between both pin tails 13 and 14 is ruptured, and screw-fitting in the base material 4 is completed, and afterward, in a condition of gripping and fixing the fastening pin tail 13, a nut is rotated, and is screw fitted to the screw part 12, and a rupture groove 15 between the screw part 12 and the fastening pin tail 13 is ruptured, and screw-fitting of the nut is completed. Since the rupture groove 16 is ruptured when the screw-fitting of the screw part 11 in the base material 4 is completed, the screw-fitting in the base material 4 is confirmed by applying constant torque.