An automated heat treatment system for an engine valve having; a furnace for heat treating engine valves, a carry-in mechanism for carrying forged engine valves into the furnace, and a carry-out mechanism for carrying heat treated engine valves out of the furnace and transferring the valves to a next processing mechanism, the heat treatment system characterized in that: the carry-in mechanism includes a first retention mechanism for retaining a multiplicity of forged engine valves hung by supporting the umbrella-shaped portions of the valves, and a first transport mechanism for transporting the retained engine valves to the furnace; the furnace includes heating means for heating the engine valves, groups of paired rails with the pair rails spaced apart in parallel at a distance smaller than the diameter of the umbrella-shaped portions but larger than the diameter of the stem portions of the valves, the paired rails adapted to retain the engine valves hung by supporting the umbrella shaped portions and movable in the longitudinal direction of the rails, and a stopper having at least one pawl which is movable in the longitudinal direction towards, and away from, the umbrella shaped portions of the valves, and the carry-out mechanism includes a second transport mechanism for retaining the engine valves hung by supporting the umbrella shaped portions and for carrying out from the furnace the heat treated engine valves as they are hung, and a second retention mechanism adapted to retain the engine valves hung by supporting the umbrella shaped portions of the valves carried out of the furnace. the carry-in mechanism includes a first retention mechanism for retaining a multiplicity of forged engine valves hung by supporting the umbrella-shaped portions of the valves, and a first transport mechanism for transporting the retained engine valves to the furnace; a first retention mechanism for retaining a multiplicity of forged engine valves hung by supporting the umbrella-shaped portions of the valves, and a first transport mechanism for transporting the retained engine valves to the furnace; the furnace includes heating means for heating the engine valves, groups of paired rails with the pair rails spaced apart in parallel at a distance smaller than the diameter of the umbrella-shaped portions but larger than the diameter of the stem portions of the valves, the paired rails adapted to retain the engine valves hung by supporting the umbrella shaped portions and movable in the longitudinal direction of the rails, and a stopper having at least one pawl which is movable in the longitudinal direction towards, and away from, the umbrella shaped portions of the valves, and heating means for heating the engine valves, groups of paired rails with the pair rails spaced apart in parallel at a distance smaller than the diameter of the umbrella-shaped portions but larger than the diameter of the stem portions of the valves, the paired rails adapted to retain the engine valves hung by supporting the umbrella shaped portions and movable in the longitudinal direction of the rails, and a stopper having at least one pawl which is movable in the longitudinal direction towards, and away from, the umbrella shaped portions of the valves, and the carry-out mechanism includes a second transport mechanism for retaining the engine valves hung by supporting the umbrella shaped portions and for carrying out from the furnace the heat treated engine valves as they are hung, and a second retention mechanism adapted to retain the engine valves hung by supporting the umbrella shaped portions of the valves carried out of the furnace. a second transport mechanism for retaining the engine valves hung by supporting the umbrella shaped portions and for carrying out from the furnace the heat treated engine valves as they are hung, and a second retention mechanism adapted to retain the engine valves hung by supporting the umbrella shaped portions of the valves carried out of the furnace.