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 (15a, 15b) 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 (15a, 15b) 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.