The invention relates to a paper shredder containing a cutting mechanism which comprises a pair of cutting rollers (4, 5) that are driven in counter-rotation and which has stripping ribs (23 or 24). Said stripping ribs project inside radial gaps (22) between the cutting discs (11, 12) thereof and the groove base of the counter-cutting rollers (5 or 4). The stripping ribs (23, 24) are fixed by snapping in a merely rotationally moveable manner on the roller cores (9 or 10) of the cutting rollers (4 or 5) which are assigned thereto, and are prevented from being rotationally driven solely thereby or by a support situated on the side of the housing.