Disclosed is a sheet processing apparatus 1 having a pair of rolls 2 and 3 with teeth on their periphery in engagement with each other. The rolls are adapted to have a sheet 10 introduced into the nip thereof while rotating to process the sheet 10. The teeth 20 (30) of the roll 2 (3) have a pitch of 1.0 to 5.0 mm, a tooth thickness of less than a half the pitch, and a tooth height equal to or more than the pitch. The depth of engagement between the teeth 20 of the roll 2 and the teeth 30 of the roll 3 is preferably 1.0 mm up to the tooth height.