Abstract: An apparatus for continuously manufacturing a corrugated sheet having a varying fold width and also having fold lines extending either straight or in wavy or zig-zag fashion in a direction widthwise thereof. The apparatus includes upper and lower toothed rolls each made up of a group of toothed discs and having a circumferential groove defined between each neighboring toothed discs. At least one of the upper and lower toothed rolls is supported for adjustment in position relative to and in a direction towards and away from the other of the upper and lower toothed rolls. Upper and lower guide bars while extending in a direction parallel to the upper and lower toothed rolls are accommodated within the circumferential grooves for movement in a direction towards and away from each other over a distance corresponding to the height of each tooth of any one of the upper and lower toothed rolls.