PURPOSE: To perform easily and exactly normal welding and to produce easily and inexpensively a multi-layered UOE pipe by tack-welding metallic plate stock to unite the stock to one body then beveling the edges thereof and forming the materials to an intended size.

CONSTITUTION: Determined metallic plate stock 10, 11 are superposed and are subjected to tack-welding 14 by a low resistance welding method near both side edges 12, 13 to unit the stocks 10, 11 to one body. The edges 12, 13 of the superposed and united stocks 10, 11 are beveled to form grooves 21, 22 for welding. The edges are so machined that at least a part of the tack-weld zones 14 remain. While the stocks 10, 11 are held united, the stocks are subjected to U working and O working and thereafter the butt grooves 21, 22 are subjected to normal welding. The multi-layered UOE pipe is thus easily and inexpensively produced.