Excircle polishing device

The utility model discloses an excircle polishing device which comprises a motor supporting seat, a driving motor, a driving toothed belt pulley, a transmission toothed belt and a driven gear, wherein the driving motor is mounted on the motor supporting seat; the driving toothed belt pulley and the transmission toothed belt are mounted on an output shaft of the driving motor; and an adjustable annular polishing mechanism is arranged in the driven gear. As the annular polishing mechanism is arranged in the driven gear, before polishing, all that is needed is to fixedly mount a to-be-polished excircle in the annular polishing mechanism, drive the driven gear through the driving toothed belt pulley to rotate, and enable the polishing mechanism and the to-be-polished excircle to do relative circumferential friction motion, so that the to-be-polished excircle can be polished. Therefore, the to-be-polished excircle is not required to be adjusted ceaselessly to ensure the cylindricity and the straightness of the pol