Planetary Gearbox comprising - a case; - a first shaft, an intermediate shaft and a second shaft, said first, intermediate and second shafts,, being supported by and rotating with respect to the case; said first, intermediate and second shafts,, being coaxial together; the first shaft and the second shaft coming out of the case; the first shaft comprising, inside the case, an end portion inclined by a predetermined angle with respect to the axis of the first shaft, - a single face stage having a single face configuration, comprising a first internal bevel gear and a second bevel gear concentric and external to the first internal bevel gear, the first internal bevel gear and the second bevel gear being integral or made integral with each other and rotating on the end portion of the first shaft in an idle manner, a third fixed gear mounted inside the case and integral thereto, having teeth converging to the center of its pitch circle such that it is coaxial with the intermediate shaft, and a fourth bevel gear, concentric and internal to the previous bevel gear and integral with the intermediate shaft, wherein the conical generatrices of the teeth of the first, second, third and fourth gears,, and have the vertex in common; said vertex coinciding with the point of intersection between the axis of the first and intermediate shafts and and the axis of the inclined end portion of the first shaft, - a double face stage having a double face configuration, comprising the intermediate shaft and the second shaft, the intermediate shaft comprising, inside the case, an end portion inclined by a predetermined angle with respect to the axis of the intermediate shaft, a fifth and sixth bevel gears and integral or made integral with each other and forming opposite sides of a disc-like structure rotating in an idle manner on the end portion of the intermediate shaft, a seventh fixed gear mounted inside the case and integral thereto, the seventh fixed gear having teeth converging to the center of its pitch circle such that it is coaxial with the second shaft, an eighth bevel gear, coaxial with the seventh fixed gear and integral with the second shaft, wherein the conical generatrices of the teeth of the fifth, sixth, seventh and eighth gears,, and have the vertex in common; said vertex coinciding with the point of intersection between the axis of the intermediate and second shafts and and the axis of the inclined end portion of the intermediate shaft, wherein the first shaft is an input shaft of the single face stage of the gearbox, the intermediate shaft is an output shaft of the single face stage and an input shaft of the double face stage, and the second shaft is an output shaft of the double face stage and thus an output shaft of the whole gearbox, or wherein the second shaft is an input shaft of the double face stage of the gearbox, the intermediate shaft is an output shaft of the double face stage and an input shaft of the single face stage, and the first shaft is an output shaft of the single face stage and thus an output shaft of the whole gearbox. - a case; - a first shaft, an intermediate shaft and a second shaft, said first, intermediate and second shafts,, being supported by and rotating with respect to the case; said first, intermediate and second shafts,, being coaxial together; the first shaft and the second shaft coming out of the case; the first shaft comprising, inside the case, an end portion inclined by a predetermined angle with respect to the axis of the first shaft, - a single face stage having a single face configuration, comprising - a double face stage having a double face configuration, comprising