To provide a polishing jig capable of rotating a cylindrical work such as a bearing outer ring accurately without a running out.

The polishing jig includes a taper ring 2 which is to be fitted on a shaft taper part 1c and is furnished with three slits 2s, 2s and 2s at a constant spacing in the circumferential direction. Each slit 2s is shaped not penetrating in the axial direction from the end face 2a on the ring thinner wall side to the end face 2b on the thicker wall side, where a communication part 2t continuing in the circumferential direction is formed in the neighborhood of the thicker wall side end face 2b of the slit 2s. Thereby the enlarging direction of the taper ring peripheral surface 2x is made 120 degree intervals, and the pushing force to the work inside surface generated by enlargement of the peripheral surface 2x can be made uniform in the circumferential direction. Accordingly the work can be secured in the condition that the rotating center of the polishing jig is located identical to that of the work, and run-out of the work periphery at the time of being ground can be suppressed.