A method for producing a transversely extensible elastic laminar web material (100, 100', 100") comprising the steps of: - feeding a first web material permeable to gases having a first and a second distal region (1021, 1022) adjacent to respective longitudinal side edges (1023, 1024) and a central region between said distal regions, - placing the first web material on the outer surface of a cylindrical roller, rotating around its own horizontal axis, - retaining said first and second distal regions (1021, 1022) on the outer surface of said roller and keeping said first web material in an extended condition by means of a plurality of suction holes and vacuum distribution means, which connect the outer surface of the roller with a sub-atmospheric pressure source, - feeding (111, 111', 1002, 1006) a plurality of connection formations, - applying said plurality of connection formations to at least one of said first and second distal regions (1021, 1022) of said first web material, said connection formations protruding from said respective longitudinal side edge (1023, 1024) of said first web material, - holding in position on the roller said plurality of connection formations by means of said suction holes connected to said sub-atmospheric pressure source by means of said vacuum distribution means, - feeding a web of elastomeric material, - coupling (126, 118) said web of elastomeric material to said first web material at said central region of said first web material, - holding in position and making to adhere said web of elastomeric material to the first web material by means of said suction holes connected to the sub-atmospheric pressure source by means of said vacuum distribution means, - feeding a second web material having a first and a second distal region (1041, 1042) adjacent to the respective longitudinal side edges (1043, 1044) and a central region between said distal regions, - coupling said second web material to said first web material with said elastomeric web material and said plurality of connection formations interposed between them, and - joining (35, 36) said elastomeric web material and said plurality of connection formations to said first and second web materials (102, 104) with mechanical welds (355, 365). - feeding a first web material permeable to gases having a first and a second distal region (1021, 1022) adjacent to respective longitudinal side edges (1023, 1024) and a central region between said distal regions, - placing the first web material on the outer surface of a cylindrical roller, rotating around its own horizontal axis, - retaining said first and second distal regions (1021, 1022) on the outer surface of said roller and keeping said first web material in an extended condition by means of a plurality of suction holes and vacuum distribution means, which connect the outer surface of the roller with a sub-atmospheric pressure source, - feeding (111, 111', 1002, 1006) a plurality of connection formations, - applying said plurality of connection formations to at least one of said first and second distal regions (1021, 1022) of said first web material, said connection formations protruding from said respective longitudinal side edge (1023, 1024) of said first web material, - holding in position on the roller said plurality of connection formations by means of said suction holes connected to said sub-atmospheric pressure source by means of said vacuum distribution means, - feeding a web of elastomeric material, - coupling (126, 118) said web of elastomeric material to said first web material at said central region of said first web material, - holding in position and making to adhere said web of elastomeric material to the first web material by means of said suction holes connected to the sub-atmospheric pressure source by means of said vacuum distribution means, - feeding a second web material having a first and a second distal region (1041, 1042) adjacent to the respective longitudinal side edges (1043, 1044) and a central region between said distal regions, - coupling said second web material to said first web material with said elastomeric web material and said plurality of connection formations interposed between them, and - joining (35, 36) said elastomeric web material and said plurality of connection formations to said first and second web materials (102, 104) with mechanical welds (355, 365).