Abstract: An apparatus for forming an absorbent pad for an absorbent sanitary article including a first layer, a second layer and an absorbent material interposed between the first and the second layer, includes: a forming drum; a first feed system for feeding to the forming drum a first web, intended to form the first layer; and a second feed system for feeding to the forming drum a second web, intended to form the second layer; at least one spreader for spreading the absorbent material on the forming drum; the first web, the second web and the absorbent material together form a composite web and the forming apparatus includes a system for joining the first and second webs and a system for calibrating the thickness of the absorbent material in the composite web and being located upstream of the joining system in a feed direction V of the composite web.