To improve an external appearance quality by facilitating the automation with reducing polishing processes and aligning circumferential polishing lines in polishing a deformed pipe, an U-shaped pipe in particular.

This polishing method is so constituted that an endless polishing cloth is stretched between two or more wheels, and while one of the wheels is rotated by a drive to move the polishing cloth, a cylindrical workpiece is pressed against the polishing cloth between the wheel and the wheel so as to be polished. This device is so rotated that the cross sectional center of the workpiece becomes almost the rotation center of a pulley and the polishing cloth, and characterized in that the workpiece is so fed and polished as to be parallel to the polishing cloth.