The present invention relates to a method of manufacturing a top sheet material (6) or back sheet material for use in the manufacture of disposable absorbent articles, comprising the steps of, a) splitting a continuous first web (1) of sheet material having substantially straight side edges (2a, 2b) into a second and third continuous web (4 and 5, respectively) by an alternating concave-convex cutting line (3) cut in a longitudinal direction along said continuous first web (1), said cutting line being distanced from both side edges (2a, 2b) of said continuous first web (1), b) shifting the second continuous web (4) in a lateral direction in relation to the third continuous web (5) so that the substantially straight edges (2a, 2b) of the second and third continuous webs are parallel to and adjacent to each other and longitudinally shifting the second continuous web (4) so that the series of concave edge portions and the series of convex edge portions of the second and third continuous webs (4, 5) are longitudinally aligned with each other, c) directly or indirectly joining the substantially straight edges of the second and third continuous webs to each other, thereby forming a composite fourth web (6). According to the invention the cutting line (3) is made in said first continuous web (1) so that all portions (3a-3d) of said cutting line (3) are distanced from a longitudinal centre line (A) of said first continuous web.
