An apparatus for forming an absorbent pad for an absorbent sanitary article, the pad comprising a first layer, a second layer and an absorbent material interposed between the first and the second layer (101, 102) and arranged according to an absorbent material spreading pattern M1 having at least one channel (104, 105) free of absorbent material where the first layer and the second layer are joined directly to each other, the apparatus comprising a forming drum, a first feed system for feeding a first web, intended to form the first layer, to the forming drum, a second feed system for feeding a second web, intended to form the second layer, to the forming drum, at least one spreader for spreading the absorbent material on the forming drum, the forming drum comprising a suction system to create on the first web disposed on the forming drum a spread of absorbent material according to the absorbent material spreading pattern M1, the forming drum comprising at least one insert in the suction system to inhibit suction at the channel (104, 105) so that the absorbent material is not retained at the channel (104, 105), the first web, the second web and the absorbent material together forming a composite web, the apparatus comprising at least one welding system for welding the first and second webs (NW1, NW2) and comprising a first welding element and a second welding element acting in conjunction with each other, the apparatus being characterized in that it comprises at least one adhesive dispenser located upstream of the spreader of the absorbent material in a feed direction V1 of the first web to apply on the first web a layer of adhesive according to a gluing pattern M2 comprising a zone (Z1, Z2) which is free of the adhesive at the channel (104, 105) and in that the first welding element has a contact surface coming into contact with the second welding element and shaped according to a welding pattern M3 comprising at least one welding zone (Z3, Z4) at the channel (104, 105). a forming drum, a first feed system for feeding a first web, intended to form the first layer, to the forming drum, a second feed system for feeding a second web, intended to form the second layer, to the forming drum, at least one spreader for spreading the absorbent material on the forming drum, the forming drum comprising a suction system to create on the first web disposed on the forming drum a spread of absorbent material according to the absorbent material spreading pattern M1, the forming drum comprising at least one insert in the suction system to inhibit suction at the channel (104, 105) so that the absorbent material is not retained at the channel (104, 105), the first web, the second web and the absorbent material together forming a composite web, the apparatus comprising at least one welding system for welding the first and second webs (NW1, NW2) and comprising a first welding element and a second welding element acting in conjunction with each other, the apparatus being characterized in that it comprises at least one adhesive dispenser located upstream of the spreader of the absorbent material in a feed direction V1 of the first web to apply on the first web a layer of adhesive according to a gluing pattern M2 comprising a zone (Z1, Z2) which is free of the adhesive at the channel (104, 105) and in that the first welding element has a contact surface coming into contact with the second welding element and shaped according to a welding pattern M3 comprising at least one welding zone (Z3, Z4) at the channel (104, 105).