A gas burner with at least two flame rings, characterised by consisting of: - an injector holder (6) provided with a single vertical injector (22) positioned centrally on the injector base, - a flame divider (4) with an outer chamber (26) of overall annular development, and an inner chamber (28) of overall circular development, between which an annular cavity (29) is interposed, - a cover (8) made in one piece and comprising a central discoidal portion (54), which upperly closes said inner circular chamber (28), and an annular portion (52) which upperly closes said outer annular chamber (26), and in that: - said flame divider (4) lowerly comprises means (30, 23) for the resting of said flame divider on said injector holder (6, 12), and its connection thereto, - the inner circular chamber (28) of said flame divider (4) comprises a single substantially vertical channel (46) facing said single vertical injector (22) of said injector holder (6), said substantially vertical conduit (46) opening into a radial chamber (47) of venturi effect defined in said inner chamber (28) of the flame divider (4) and upperly bounded by the central discoidal portion (54) of said cover (8), - said flame divider (4) comprises at least one substantially radial channel (36) for fluidic connection between said inner circular chamber (28) and said outer annular chamber (26), said radial chamber (36) being closed upperly by a corresponding radial part (56) of said cover (8), - said at least two flame rings comprising a first ring of flames, generated at ports (42, 43) provided in the outer wall (32) of said outer annular chamber (26) of the flame divider (4), and at least one second ring of flames which can be generated at ports (42, 43) provided in the inner wall (34) of said outer annular chamber (26) of the flame divider (4), or at ports (42, 43) provided in the lateral wall (35) of said inner chamber (28) of the flame divider (4) or at ports (42, 43) provided in both the inner wall (34) of said outer annular chamber (26) and said lateral wall (35) of said inner circular chamber (28).