Abstract: The automatic bar feeder device comprises a loading device that loads or unloads a bar from a hopper while avoiding shock exerted by the bar against an element of the magazine bar feed, the bar to be treated being seized by claws (42) which transport the bar towards the bench (22) and lay it smoothly down there. The movements of the loading device (40) are reversible so that it is able to act also as an unloading device. The loading/unloading device (40) cooperates with the long advance device (70) thanks to a combination of movements. Finally, the short advance device (40) and the long advance device (70) are driven for advancing the bar into a lathe, by one and the same element (98), the two devices are able to be coupled and uncoupled through a latching/unlatching device (80).