Abstract: The invention relates to a burner (1) which is operated with a lean gas (8) (LBTU gas) and comprises at least two hollow, conical partial bodies (2, 3) which are nested in one another in the direction of flow. By offsetting the longitudinal axes of symmetry (2a, 3a) relative to one another, tangential ducts (2b, 3b) are formed through which combustion air (4) flows into the conical cavity (5). Parallel to these ducts (2b, 3b) there are further ducts (6, 7), formed by dividing walls (6a, 7a), through which the-lean gas (8) likewise flows into the conical cavity (5) at a similar rate to the combustion air (4).