A gas burner with multiple rings of main flames includes an injector holder structure; a central distribution chamber within a central flame divider element that is rigid with the injector holder structure, generates a central ring of flames, and is closed by a circular cover; an annular distribution chamber having an annular flame divider element that is rested on the injector holder structure, generates at least one ring of main flames concentric with the central ring of flames, is separated from the central distribution chamber by an annular space, and is closed by an annular cover; and first and second venturi conduits that are substantially horizontal and parallel, are situated in the injector holder structure outline, and have inlet ends facing injectors associated with a wall of the injector holder structure and outer ends opening into cavities communicating with the central distribution chamber and with the annular distribution chamber.