Method for manufacturing a wing-box for aircraft, comprising the steps of: a1) arranging, on a curing surface , a first panel of composite material, comprising a skin having a first side and a plurality of stringers that extend parallel to a longitudinal direction (x); a2) providing a plurality of ribs of non-polymerized composite material, each comprising a plate , a first pair of flanges and a second pair of flanges , each pair of flanges being arranged at opposed ends of said plate , and each rib having a plurality of through openings spaced along an edge of the plate ; a3) providing a plurality of support inserts , each comprising a bridge element , an extrados surface arranged to be put in contact with a respective opening of a rib , an intrados surface , arranged to be placed on a caul plate , and a base portion ; b1) arranging, on each stringer , a caul plate having a cross-section shape that covers the respective stringer ; b2) arranging, on said first side of the first panel , aligned along the transverse direction (y), pluralities of support inserts , so that the intrados surface of each support insert rests on a respective caul plate , and that the base portion of each support insert rests on the skin of the first panel and/or on a respective caul plate arranged on a stringer ; b3) arranging, on said first side of the first panel , a plurality of ribs , spaced in the longitudinal direction (x), wherein the respective first pair of flanges of each rib rests on said first side of the first panel , and wherein the respective plurality of openings of each rib rests on the extrados surfaces of a plurality of aligned support inserts , so that each stringer extends through a respective opening of each rib ; c) having the first panel and the plurality of ribs undergo a curing process in autoclave with vacuum bag, according to a specific pressure and temperature cycle, for curing the non-polymerized components. a1) arranging, on a curing surface , a first panel of composite material, comprising a skin having a first side and a plurality of stringers that extend parallel to a longitudinal direction (x); a2) providing a plurality of ribs of non-polymerized composite material, each comprising a plate , a first pair of flanges and a second pair of flanges , each pair of flanges being arranged at opposed ends of said plate , and each rib having a plurality of through openings spaced along an edge of the plate ; a3) providing a plurality of support inserts , each comprising a bridge element , an extrados surface arranged to be put in contact with a respective opening of a rib , an intrados surface , arranged to be placed on a caul plate , and a base portion ; b1) arranging, on each stringer , a caul plate having a cross-section shape that covers the respective stringer ; b2) arranging, on said first side of the first panel , aligned along the transverse direction (y), pluralities of support inserts , so that the intrados surface of each support insert rests on a respective caul plate , and that the base portion of each support insert rests on the skin of the first panel and/or on a respective caul plate arranged on a stringer ; b3) arranging, on said first side of the first panel , a plurality of ribs , spaced in the longitudinal direction (x), wherein the respective first pair of flanges of each rib rests on said first side of the first panel , and wherein the respective plurality of openings of each rib rests on the extrados surfaces of a plurality of aligned support inserts , so that each stringer extends through a respective opening of each rib ; c) having the first panel and the plurality of ribs undergo a curing process in autoclave with vacuum bag, according to a specific pressure and temperature cycle, for curing the non-polymerized components. <EOS>