An apparatus for producing an elastic composite tape with intermittent elastic sections (72', 72"), comprising: - a tensioning unit for longitudinally tensioning a continuous elastic film, - a cut and repitch unit comprising a knife roller and a repitch device comprising a plurality of transport units and a plurality of anvils (30, 30') cooperating with the knife roller to transversely cut the tensioned continuous elastic film and to form a succession of discrete sections of elastic film (72', 72"), wherein the transport units retain - by suction - respective discrete sections of elastic film (72', 72") alternately spaced apart from each other by a first predetermined distance and by a second predetermined distance, with said first distance greater than said second distance, wherein the first distance is comprised between 5 and 50 mm, in particular between 10 and 20 mm, and wherein the second distance is comprised between 100 and 300 mm, in particular between 150 and 250 mm, wherein each of said transport units comprises a first section and a second section (32"), wherein said transport units retain said discrete sections of elastic film (72', 72") spaced apart from each other by said first distance and said first section and second section (32") of each transport unit retain said discrete sections of elastic film (72', 72") spaced apart from each other by said second distance, - a welding unit comprising an anvil roller and a welding head cooperating with the anvil roller, wherein the anvil roller has a cylindrical contrast surface provided with a plurality of protruding teeth having head surfaces forming counter-welding surfaces that cooperate with said welding head, wherein the anvil roller has a plurality of pairs of suction sections (86', 86") provided with holes that communicate with a suction cavity connected to a sub-atmospheric pressure source, wherein each suction section (86', 86") has a length equal to the length of the stretched elastic sections (72', 72"), wherein the suction sections (86', 86") of each pair are spaced apart from each other by a distance equal to said second distance between successive elastic sections (72', 72"), and wherein said pairs of suction sections (86', 86") are spaced apart from each other by a distance equal to the first required distance between successive elastic sections (72', 72"), - a tangency zone between the transport units and the anvil roller, in which respective discrete sections of elastic film (72', 72") are transferred to said at least one suction section of the anvil roller, - a first feeding system for feeding a first web material to the anvil roller upstream of said tangency zone, and - a second feeding system for feeding a second web material to the anvil roller between said tangency zone and said welding head. - a tensioning unit for longitudinally tensioning a continuous elastic film, - a cut and repitch unit comprising a knife roller and a repitch device comprising a plurality of transport units and a plurality of anvils (30, 30') cooperating with the knife roller to transversely cut the tensioned continuous elastic film and to form a succession of discrete sections of elastic film (72', 72"), wherein the transport units retain - by suction - respective discrete sections of elastic film (72', 72") alternately spaced apart from each other by a first predetermined distance and by a second predetermined distance, with said first distance greater than said second distance, wherein the first distance is comprised between 5 and 50 mm, in particular between 10 and 20 mm, and wherein the second distance is comprised between 100 and 300 mm, in particular between 150 and 250 mm, wherein each of said transport units comprises a first section and a second section (32"), wherein said transport units retain said discrete sections of elastic film (72', 72") spaced apart from each other by said first distance and said first section and second section (32") of each transport unit retain said discrete sections of elastic film (72', 72") spaced apart from each other by said second distance, - a welding unit comprising an anvil roller and a welding head cooperating with the anvil roller, wherein the anvil roller has a cylindrical contrast surface provided with a plurality of protruding teeth having head surfaces forming counter-welding surfaces that cooperate with said welding head, wherein the anvil roller has a plurality of pairs of suction sections (86', 86") provided with holes that communicate with a suction cavity connected to a sub-atmospheric pressure source, wherein each suction section (86', 86") has a length equal to the length of the stretched elastic sections (72', 72"), wherein the suction sections (86', 86") of each pair are spaced apart from each other by a distance equal to said second distance between successive elastic sections (72', 72"), and wherein said pairs of suction sections (86', 86") are spaced apart from each other by a distance equal to the first required distance between successive elastic sections (72', 72"), - a tangency zone between the transport units and the anvil roller, in which respective discrete sections of elastic film (72', 72") are transferred to said at least one suction section of the anvil roller, - a first feeding system for feeding a first web material to the anvil roller upstream of said tangency zone, and - a second feeding system for feeding a second web material to the anvil roller between said tangency zone and said welding head.