Abstract: An electric furnace has an inlet opening for introduction of starting materials in the upper region thereof. A pre-melting vessel is arranged above the furnace and has a discharge opening above and in communication with the inlet opening of the furnace. The bottom portion of the furnace is formed with a depression in which the starting material forms a body after its introduction through the inlet opening and is heat-treated so as to obtain slag and steel. The furnace is provided at its sides with a pair of mounting members each having a cam surface of part-circular configuration having a center on an axis which extends substantially horizontally and is located at the inlet opening of the furnace. A plurality of rollers engages the cam surfaces, the rollers being mounted on a support for rotation about their axes.