Method for assembling a planet carrier, said planet carrier having an axis of revolution and comprising: - an annular cage comprising: - a series of posts distributed circumferentially around the axis of revolution, each post comprising an internal saddle and an external saddle in each of which is formed a through opening (23, 25), - bearing seats defining bores configured to receive a bearing of a planet gear, - an annular cage carrier comprising: - a series of axial fingers distributed circumferentially around the axis of revolution in each of which is formed a through opening, each axial finger being configured to be accommodated between the internal saddle and the external saddle of a post of the cage, - a shaft coaxial with the axis of revolution and having at least one rolling seat (41, 42), said shaft being attached to the cage carrier, the assembly method being characterized in that it comprises the following steps: - separately producing the cage and the cage carrier while providing excess thickness at one of the following elements: the through opening of the internal saddle and the through opening of the external saddle of at least one post of the cage or the through opening of at least one finger of the cage carrier and/or at one of the following elements: at least one bearing seat or the at least one rolling seat (41, 42), - assembling the cage and the cage carrier by placing each axial finger of the cage carrier between an internal saddle and an external saddle of the cage, - positioning the cage with respect to the cage carrier and attaching together the cage and the cage carrier so as to achieve a single-piece assembly, - determining a position of at least one reference axis (Y1, Y2) linked to the cage, to the cage carrier and/or to the shaft and - while taking into account the position of at least one of the reference axes (Y1, Y2), machining all or part of the excess thicknesses so as to ensure alignment between the through openings of each internal saddle and of each external saddle with the through opening (23, 25) of the associated axial finger on the one hand, and/or of the bearing seats of the cage with the rolling seat (41, 42) on the other hand. - an annular cage comprising: - a series of posts distributed circumferentially around the axis of revolution, each post comprising an internal saddle and an external saddle in each of which is formed a through opening (23, 25), - bearing seats defining bores configured to receive a bearing of a planet gear, - a series of posts distributed circumferentially around the axis of revolution, each post comprising an internal saddle and an external saddle in each of which is formed a through opening (23, 25), - bearing seats defining bores configured to receive a bearing of a planet gear, - an annular cage carrier comprising: - a series of axial fingers distributed circumferentially around the axis of revolution in each of which is formed a through opening, each axial finger being configured to be accommodated between the internal saddle and the external saddle of a post of the cage, - a shaft coaxial with the axis of revolution and having at least one rolling seat (41, 42), said shaft being attached to the cage carrier, - a series of axial fingers distributed circumferentially around the axis of revolution in each of which is formed a through opening, each axial finger being configured to be accommodated between the internal saddle and the external saddle of a post of the cage, - a shaft coaxial with the axis of revolution and having at least one rolling seat (41, 42), said shaft being attached to the cage carrier, - separately producing the cage and the cage carrier while providing excess thickness at one of the following elements: the through opening of the internal saddle and the through opening of the external saddle of at least one post of the cage or the through opening of at least one finger of the cage carrier and/or at one of the following elements: at least one bearing seat or the at least one rolling seat (41, 42), - assembling the cage and the cage carrier by placing each axial finger of the cage carrier between an internal saddle and an external saddle of the cage, - positioning the cage with respect to the cage carrier and attaching together the cage and the cage carrier so as to achieve a single-piece assembly, - determining a position of at least one reference axis (Y1, Y2) linked to the cage, to the cage carrier and/or to the shaft and - while taking into account the position of at least one of the reference axes (Y1, Y2), machining all or part of the excess thicknesses so as to ensure alignment between the through openings of each internal saddle and of each external saddle with the through opening (23, 25) of the associated axial finger on the one hand, and/or of the bearing seats of the cage with the rolling seat (41, 42) on the other hand.