To provide a polishing device making a partition plate for dividing partition chambers movable, and feely storing a workpiece even if the size, shape and like thereof is nonstandardized.

This polishing device comprises a partition plate 8 stored in a polishing tank 2 and dividing partition chambers 9; a rotating mechanism portion 15 connecting to the partition plate 8, making the partition plate 8 move toward a circumferential direction of the polishing tank 2 when inserting the partition plate 8 into the polishing tank 2, and making the partition plate 8 move in a radius direction of the polishing tank 2 after inserting the partition plate 8 into the polishing tank 2; and a canopy 6 connecting to the rotating mechanism portion 15.