This torque transmission mechanism (A), for a starter for an internal combustion engine, is adapted to transmit a starting torque from a starter motor to a crankshaft (4). The torque transmission mechanism (A) comprises a ring gear (2) that transmits the starting torque and a one-way clutch (8) disposed between the ring gear (2) and the crankshaft (4), this ring gear (2) comprising a gear side portion (22) to which the starting torque is transmitted from the starter motor via gear mesh, and a flange (24) extending between the gear side portion (22) and an inner ring (82) of the one-way clutch (8). The flange (24) comprises an inner section (240) which forms the inner ring (82) of the one-way clutch (8) and an outer section (242) fixed to the inner section (240) and on which the gear side portion (22) is fixed. The inner and outer sections (240, 242) of the flange (24) are fixed together by a mechanical assembly other than welding.
