To provide a polishing device easily polishing a surface of a tapered member.

This tapered member polishing device (for example, an electric pole polishing device 100) polishes the surface of the tapered member (for example, an electric pole 200) by moving polishing parts 110a and 110b rotating around a shaft of the tapered member (for example, the electric pole 200) in the shaft direction of the tapered member (for example, the electric pole 200) along the surface of a housing 150 and the tapered member (for example, the electric pole 200) arranged inside the housing 150. A turning radius of the polishing parts 110a and 110b rotating around the shaft of the tapered member (for example, the electric pole 200) changes in response to a change in a diameter of the tapered member (for example, the electric pole 200).