Gas burner for oven, or grill, of the type comprising at least one Venturi tube (16), for forming the fuel mixture of primary air-gas, having at least one zone with a reduced section followed by a zone with a diverging section, at least one distribution chamber (17) of the fuel mixture, placed downstream the zone with a diverging section of the Venturi tube (16), and a plurality of flame openings (19) for the outflow of the fuel mixture, obtained within such a distribution chamber (17), or in fluidic communication with the latter, as well at least one ignition hole (13) for igniting the burner. Advantageously the latter comprises at least one diversion duct (12) for part of the flow of the fuel mixture, exhibiting its own inlet section obtained in a sector downstream the zone with a reduced section of the Venturi tube (16), and its own outlet section placed at the afore said ignition hole (13).