The present disclosure relates to the lubrication of a planet-carrier for a mechanical reduction gear of a turbine engine, for example of an aircraft. The planet-carrier includes a cage defining an internal housing configured to receive a central sun gear with an axis of rotation X, and an annular row of planet gears arranged around the sun gear. The cage includes two annular walls that are radial with respect to the axis X, and connected to one another at their outer periphery by a cylindrical wall. At least one of the radial walls has orifices for mounting the planet gears, and the cylindrical wall has through-holes for the passage of the gearings of the planet gears so that they may engage with a gearing of the ring gear, which is configured to extend around the planet gears and the cage.