Abstract: An electric melting furnace is provided with an exit comprising an overflow dam and a downwardly extending unmolten-substances blocking plate placed inwardly of the overflow dam. The exit is positioned on or near an extension of a line connecting the center O of a furnace body and one of the furnace electrodes, the distance L in centimeters between the electrode and the overflow dam being determined by the equation: ##EQU1## where P is the electric furnace load (w) and K is a constant in the range of 16 to 25. Lighter molten substances are continuously discharged over the dam under the weight of the combustion residue. Heavier molten metals accumulate on the furnace floor and are discharged over dam by tilting the furnace body in the direction of the exit.