Machine for continuous casting of a lead alloy for forming grids for plates of electric storage batteries, which comprises a rotary drum having an external peripheral surface with a plurality of grooves obtained according to the grid design to be made and a sliding block coupled in sliding relation with the external surface of the rotary drum and with a distribution duct obtained in order to insert the molten lead in the plurality of grooves. The plurality of grooves comprises circumferential notches and transverse notches that meet in respective vertices. At the vertices and within the circumferential notches, a plurality of studs are placed that are intended to shape corresponding corners of smoothed form of the grids.