Abstract: In a holder attached state in which a holder upper part 11 is attached to a brush rotation shaft 2, the lower surface of the holder upper part 11 and the inner peripheral surface of a holder lower part 18 define a brush accommodating space 23, and the inner peripheral edge of a holder bottom plate part 19 defines a circular holder opening 24 having a smaller diameter than the inner diameter of the holder lower part 18. A held part 31 of a brush body 30 is in a circular column shape incapable of penetrating through the holder opening 24, and is accommodated and held in the brush accommodating space 23. A cleaning part 32 of the brush body 30 is in a circular column shape smaller in diameter than the held part 31 and capable of penetrating through the holder opening 24, and penetrates through the holder opening 24 and projects downward.