PURPOSE: To produce a double pipe having a secure joint part by fitting a ceramic pipe to a metallic pipe via a thermally sprayed layer or the like contg. a metallic material formed on the circumferential surface of the ceramic pipe, sealing hermetically the contact boundary part and subjecting the pipe to hot hydrostatic pressurization.

CONSTITUTION: The outside circumferential surface of a ceramic pipe 1 is formed to a rough surface having much ruggedness and a thermally sprayed layer or packed layer 2 contg. a metallic material at least in a part thereof is formed on such rough surface by using metallic powder or a mixture composed of the metallic powder and ceramic powder. Such pipe 1 is fitted into a metallic pipe 3 and the contact boundary part between the thermally sprayed layer or the packed layer 2 and the pipe 3 at the end face thereof is hermetically sealed 4 by electron beam welding of by using a suitable sealing member, etc. The assembly is then put into a hot hydrostatic pressurizing furnace 5 where the pipes are heated to a high temp. and high pressure is acted thereon from the entire circumference via a pressure medium such as gaseous Ar. The double pipe consisting of the pipe 1 and the pipe 3 which are metallurgically securely united and bound is thus obtd.