PURPOSE: To obtain a burner for operating a gas turbine group or the combustion chamber and combustor of a flame apparatus in which a high flame extinguishing field can be generated regardless of the flow rate.

CONSTITUTION: A burner having an inner preliminary mixing zone comprises at least two hollow cones 1, 2 disposed vertically in the flow direction and the longitudinal symmetric axes thereof extend while being shifted from each other in the radial direction. The cones 1, 2 define a tangential air inlets slit 19, and the like, disposed on the opposite side in parallel with the flow for the combustion air stream 15 in the inner chamber of the burner, and the slit has a shape of conical hollow chamber 14. A nozzle 3 for jetting gaseous fuel is present in the conical hollow chamber 14. The tangential air inlets slit 19, and the like, are closed by a closing part 24, or the like, in the region of the nozzle 3.