Abstract: This invention concerns an electric arc furnace comprising a chamber suitable for containing molten steel; a roof suitable for covering the chamber and for containing a mass of scrap steel; electrodes suitable for melting the mass of scrap, and means of support on a base. The latter means are such as to support the chamber and permit its oscillation around a horizontal axis of rotation. The roof and the chamber are counterprofiled in correspondence to the respective interface walls to create a rotoidal type coupling with regard to the axis of rotation. The roof, during oscillation of the chamber, remains fixed with regard to the base as well as in a closed position with regard to the chamber.