PURPOSE: To curl a sheet to its both end parts in the width direction by providing rolls, integrally supported by a common shaft to a drive roller, and driven rolls, forcing their peripheral surface coming into press contact with these rolls, in the vicinity of both ends of the sheet in its width direction and tilting contact surfaces of the rolls of the drive roller with the driven rolls for the sheet in its kneed direction.

CONSTITUTION: Contact surfaces of drive rolls 131, 132 and 135, 136 respectively with driven rolls 161, 162 and 165, 166 are tilted in a direction spreading toward the center of a sheet. Consequently, holding the sheet S to be put between the drive rolls 131, 132 and 135, 136 and the driven rolls 161, 162 and 165, 166, the sheet S is discharged forming its both end parts S1, S2 to be kneed by a curl facing to the bottom. Thus forming the sheet S to be kneed usefully for its conveyance, the generation of a wrinkle can be prevented.