PURPOSE: To restrict deformation of a lining, while inside surface of a non-magnetic metallic pipe is covered with insulating lining, thermosetting resin is injected through one or more of penetrating holes are perforated in the pipe and filling with this resin between pipe and lining.

CONSTITUTION: A non-magnetic metal pipe 1 permits elongation of its length to any desired lengths with flanges 2 on both ends. In the inside surface of the pipe 1 a lining 5 is coated with insulating material, such as fluoroplastics, etc. One or more of penetrating holes 20a, 20b are perforated in the body of the pipe 1 depending upon the length of the pipe and thermosetting plastic 21 is injected through these holes for filling a space opened between pipe 1 and lining 5. Then, the resin 21 is allowed to dry by heating with a heat not affecting the lining 5 or keeping it at ambient temperature. Thus, the lining 5 is strengthened for preventing deformation of the lining and the wall thickness of the pipe may remain thin.