Device for guiding and directing a metal sheet in a bending machine to form continuously a conical structure, in particular a frustoconical structure, said device comprising: - resting and contrasting means (4; 104; 204) extending along a closed path, and suitable for restingly receiving a longitudinal edge (E) of said metal sheet and contrasting a movement of said edge (E) in a direction that is transverse to a preset advancement trajectory (T) of said metal sheet , - a supporting body (S) for said resting and contrasting means (4; 104; 204), having at least one oblong lateral portion that is suitable for facing said edge (E) and configured for conforming said resting and contrasting means (4; 104; 204) to the longitudinal profile of said edge (E) so as to obtain an extended zone of contact with said edge (E) and impress contrasting pressure distributed along said edge (E), - said resting and contrasting means (4; 104; 204) being movable around said supporting body (S) along said closed path to accompany said edge (E) of the metal sheet by a distributed contact devoid of relative sliding and rolling, so as to impose on said metal sheet the movement along said preset advancement trajectory (T) to and through said bending machine , said device being CHARACTERIZED IN THAT said supporting body (S) consists of several reciprocally connected parts (12, 13, 14, 15, 16; 17, 18, 19; 62, 63, 64; 71), the reciprocal position of said parts being variable by adjusting means (20, 21, 22; 65; 72) so as to modify the geometrical shape of said supporting body (S) to adapt the shape of the closed path of said resting and contrasting means (4; 104; 204) to the longitudinal geometric profile of said edge (E) of the metal sheet . - resting and contrasting means (4; 104; 204) extending along a closed path, and suitable for restingly receiving a longitudinal edge (E) of said metal sheet and contrasting a movement of said edge (E) in a direction that is transverse to a preset advancement trajectory (T) of said metal sheet , - a supporting body (S) for said resting and contrasting means (4; 104; 204), having at least one oblong lateral portion that is suitable for facing said edge (E) and configured for conforming said resting and contrasting means (4; 104; 204) to the longitudinal profile of said edge (E) so as to obtain an extended zone of contact with said edge (E) and impress contrasting pressure distributed along said edge (E), - said resting and contrasting means (4; 104; 204) being movable around said supporting body (S) along said closed path to accompany said edge (E) of the metal sheet by a distributed contact devoid of relative sliding and rolling, so as to impose on said metal sheet the movement along said preset advancement trajectory (T) to and through said bending machine , said device being CHARACTERIZED IN THAT said supporting body (S) consists of several reciprocally connected parts (12, 13, 14, 15, 16; 17, 18, 19; 62, 63, 64; 71), the reciprocal position of said parts being variable by adjusting means (20, 21, 22; 65; 72) so as to modify the geometrical shape of said supporting body (S) to adapt the shape of the closed path of said resting and contrasting means (4; 104; 204) to the longitudinal geometric profile of said edge (E) of the metal sheet . <EOS>