PURPOSE: To provide a metal pipe supporting fitting for surely supporting a metal pipe free from being deformed when the relatively thin metal pipe is corrected in straightly and truely circular shape or polishing- or cutting- machined.

CONSTITUTION: An elastic tube 2 which is expandable such as vinyl tube is wound in spiral form on the outer periphery of a supporting core member 1 which is straightly cylindrical and rigid, and inserted into a metal pipe 7 as worked article, and the elastic tube 2 is expanded by sending the fluid under pressure into the elastic tube 2, and the elastic tube 2 is closely attached on the inner peripheral surface of the metal pipe 7.