To reliably fix an inside surface cathode at electrolytic polishing time of a pipe, and uniformly polish a polishing object pipe inside surface without leaving a polishing failure place by forming a small diameter cylindrical opening part in succession to large diameter cylindrical opening parts so as to penetrate through a solid cylindrical body in the shaft direction.
A bar-shaped inside surface cathode is inserted into a small diameter cylindrical opening part 9, large diameter cylindrical opening parts 8a and 8b and a polishing object pipe, and a screw is screw-fitted to a polishing object body fixing screw part 12, and the polishing object pipe is fixed to a jig, and an electrolyte introducing pipe is screw-fitted to an inserting part 10, and a valve is installed in a discharge port. Inside and outside surfaces of the pipe are electrolytically polished by an anode connected to the pipe, an inside surface cathode and an outside surface cathode while forcedly circulating electrolyte by a circulating pump fixed to the outside of a tank after the valve is closed.
NAKADA IWAO
YAMAMOTO NOBORU
