PURPOSE: To realize the securing of a handle and a blade part having stable feeling by inserting the blade part insertion part grasped in a setting part into the handle insertion port in a heated and softened state on a setting plate through sliding of a slide then pressure-welding rivets into the handle-insertion hole and pressing the handle from the sides.

CONSTITUTION: A handle 8 is injection molded with a synthetic resin of high mold shrinkage factors, such as PP, and it is parted from the mold in a heated and softened state of imperfect shrinkage in the shortest cooling time. The molding is then placed on a handle setting plate 10. On the other hand, a blade part 12 is placed in the home position on the blade part setting plate 13 on a blade part slide 5 and the blade part 12 is firmly grasped and fixed by grasping plates 14, 14'. Next, the entire part of the slide 5 is slided in the handle setting part 3 direction to insert the insertion part of the blade part 12 into a handle 8 insertion port. In this state, the rivets 37, 37'... from rivet supply parts 6, 6' are inserted and pressure welded into the fitting holes of the handle 8. In addition, pressure is exerted in both side directions of the handle 8 by pressing parts 7, 7' and the blade part 12 and the handle 8 may be perfectly secured by this pressing and the shrinkage of the resin molding.