This invention relates to a device for forming a composite web of an absorbent pad for absorbent articles, such as diapers, comprising an extruding means for extruding a thermoplastic material and a delivery means for delivering superabsorbent polymer material; a suction forming surface is configured to receive the filaments of thermoplastic material blown out of the one or more delivery mouths of the extruding means and to receive the superabsorbent polymer material coming out of the delivery means, to make a composite, meltblown web comprising the superabsorbent polymer material; the delivery means has at least one outlet mouth for feeding superabsorbent polymer material and configured to be movable at least from a first distance to a second distance, or vice versa, relative to the delivery mouth of the extruding means in such a way as to vary the concentration of the superabsorbent polymer material in the composite web.