A corrugator unit, particularly for sheets or webs of paper, or similar, of the type comprising at least two rolls (1, 2), having a toothed or corrugated surface (101, 202), and being mutually engaged and pushed against each other by a predetermined pressure or force. The invention provides that the mutual compression between rolls (1, 2) is exerted (4, 5, 106, 21, 22, 25, 26) over the whole axial length of the rolls (1, 2). This may be obtained through mechanical (6) or magnetic (21, 22, 23, 25, 26) means.