To join belt-like metal plated with each other without spending an equipment cost, further without damaging the belt-like metal plates.

End parts of the belt-like metal plates 22, 24 are caulking-joined with each other by a caulking-joining machine 14. Since the caulking/joining method is applied, the component cost is reduced. Further, after caulking, adhesive tapes 30, 30 are stuck on the whole of caulking/joining 28. By this method, the whole of the caulking/joining part 28 is covered by the adhesive tape 30, spattering of a cutting chip from a web at caulking/joint is prevented. Thus, the webs are joined without damaging the web.