Support bearing for a roll (33) for immersion in liquid metal, comprising an internal rotating bush (31) fitted coaxially on a pin (32) at the end of the roll (33), and rotating inside an external bush (34) fixed to a supporting arm (37) of the roll (33). The first bush (31) is provided with an axial helical groove (39) on its outer surface and the second bush (34) is provided with a toroidal-shaped convex outer surface to allow rotation without friction inside the cylindrical ring of the supporting arm (37).