Abstract: A document shredding machine comprising a cutter assembly including cutter discs mounted separately in two rows on respective shafts for rotation in opposite directions about respective parallel axes, the discs of one row being arranged to enter gaps between the discs of the other row, wherein each disc is formed with a plurality of notches in its periphery and axially successive discs along the length of the cutter assembly are arranged with their notches circumferentially staggered in relation to one another in such a way as to eliminate the jerky action which occurs if the notches are aligned with one another and in such a way as to prevent an overall tendency for axial movement of the discs if the notches are progressively and uniformly offset from one another.