PROBLEM TO BE SOLVED: To provide a brick structure of a reflux pipe and an immersion pipe which is reduced in erosion in joints between the reflux pipe and the immersion pipe of an RH vacuum degasser and prevented in leak of atmosphere and is excellent in workability in repair.SOLUTION: In a brick structure of a reflux pipe and an immersion pipe of an RH vacuum degasser, a pipe conduit allowing molten steel to pass through is formed by joining a reflux tube 13 composed of a cylindrical reflux pipe brick 22 consisting of a joint-less molding with an immersion pipe 14 composed of a cylindrical immersion pipe brick 26 consisting of a joint-less molding by a steel-made flange 15 arranged in the lower end of a leg part 7A of a vacuum tank and a steel-made flange 15A arranged in the immersion pipe. The upper end surface of the cylindrical immersion pipe brick is joined with the lower end surface of the cylindrical reflux pipe brick at an upper position in the vertical direction relative to the joint surface of the
