To provide a paper dust removing apparatus which can attain shortening of paper dust removing treatment time by removing paper dust adherent to a side face of a stack of paper formed by piling up sheets of flat paper while making an unremoved extent to minimum and which can contribute to increase of productivity corresponding to a sheet manufacturing process.

A wiping-off device 40 which is equipped with a cylindrical brush 71 of shorter length in an axial direction than height of the stack of paper L corresponding to each of the side face of the stack of paper L conveyed by a conveying device 2, is provided. The wiping-off device 40 is made to be freely movable between a position where the cylindrical brush 71 comes into contact with each of the side face of the stack of paper L and a position where the cylindrical brush 71 retreats from a conveying region of the stack of paper L and further the cylindrical brush 71 is made to be movable both in a vertical direction and a horizontal direction. When the cylindrical brush 71 is moved alternatively in the vertical direction and the horizontal direction while being brought into contact with the side face of the stack of paper L and being rotated, paper dust removing treatment can be carried out on whole regions of the side face thereof.