Abstract: This automatic device for the putting in place of the valves of an internal combustion engine serves to insert half cones in a collar on the valve stem. Within a housing provided with a cover it comprises:a central slide displaceable in the direction indicated by the arrow A between a withdrawn position and a position of presentation of the double cones arranged on each side of the slide;a pair of jaws sliding on shafts, which jaws are spread apart when the slide is in presentation position, each jaw receiving a lever adapted to hold a half cone in its lower part and to push it towards the inside; andpush means cooperating with the collar in order to compress the valve spring in synchronism with the movement of the slide.This device operates whatever the inclination of the valve. Due to their small overall dimension, several devices can be placed alongside of each other.