To secure the strength and orientation of brazind at the time of attaching a nozzle pipe or the like by piercing a through hole with a punch and forming a cylindrical burring wall after pressing a part of a pipe wall from the outside to form a recessed part.

A part of the outer peripheral wall of a metallic pipe wall is pressed by a press machine to form a recessed part 2 with a flat bottom surface of a prescribed width. A bottom part 3 of the recessed part 2 is pressed in the direction toward the inside of the pipe by a press system using a prescribed width punch 8 to pierce a through hole 4 and at the same time, a cylindrical burring wall 5 extending in the radial direction on the inner peripheral surface of the pipe is formed. With this burring wall 5, an opening edge 6 is formed which is longer than the thickness of the metallic pipe 1 and located at an opening on the outer peripheral surface side of the pipe. The width of the recessed part 2 formed by the press is properly decided according to the diameter of the metallic pipe 1 and the diameter of the through hole 4 and the depth is decided at a level not to generate a flagging part on the opening edge 6 on the outer peripheral surface side of the pipe. The direction of the through hole 4 against the pipe center line may be properly decided as necessary.