Device for starting an internal combustion engine

The device has an epicycloidal speed reducing gear train (19) that rotatably connects a pulley (80) to an armature shaft and comprises rotation axles (38) connected to the pulley. The train comprises a ring gear (44) fixed with respect to a casing (48) and including an inner tooth that meshes with planet gears (36). The gears (36) are mounted in a freely rotating manner on the pulley which constitutes planet carriers of the train.