The invention relates to a method and an apparatus for the synchronization of cutting elements (6, 7) in a cross-cutter for a web-like material (8), wherein the web (8) to be cut is fed between rolls (1, 2) provided with the cutting elements (6, 7). The rolls (1, 2) are functionally connected by means of at least one belt-like synchronization element (5) linking the rolls and exterior of the web run (8). The invention relates also to a continuous-action cross-cutter assembly for a web-like material (8), such as a web of pulp or the like, as well as to a continuous-action sheet cutting unit for a pulp drying machine.