To achieve excellent productivity and cost reduction in a method for manufacturing a fuel filler pipe 10 (branch pipe) wherein a breezer pipe 30 is branched from a filler pipe body 20.

In the method for manufacturing a branch pipe, first and second extruded pipe bodies 20P and 30P are extruded and subsequently shaped by the molding surfaces of the dies 71 arranged on both sides of the first and second extruded pipe bodies 20P and 30P while feeding the dies 71 not only to respectively form the filer pipe body 20 and the breezer pipe 30 but also to thermally weld one end of the second extruded pipe body 30P to the outer wall of the first extruded pipe body 20P to form a welded joining part 32 for sealing the opening end of the breezer pipe 30. A communication hole 31 for connecting the respective passages of the filler pipe body 20 and the breezer pipe 30 is formed to the welded joining part 32 by the tool inserted from the opening 25Aa of a first pipe.