Abstract: A low-voltage electric heating device for application in a carburizing furnace is provided with an outer housing or sleeve for replaceable disposition within the furance, the outer housing radiating heat directly into said furnace; at least one current path conductor is positioned within the outer housing, the current path conductor being electrically connectable to a source of power and electrically insulated from a substantialy part of the outer housing. The heat radiated from the heating device is concentrated in the lower part because a current path has in series at least the current path conductor and at least a corresponding part of the outer housing, the resistance of the lower part of the outer housing being relatively large with respect to the remainder of the current path.