A burner for combustion of nitrogen-containing fuels. The burner includes a core-air tube with centrally arranged oil atomizing lance, a dust tube surrounding the core-air tube, a mantle-air tube which surrounds the dust tube and is provided with an axially shiftable twist-blade ring arranged at the air inlet, as well as a burner opening which expands conically toward the combustion chamber. The core-air tube and the mantle-air tube are supplied from a main air conduit. Air jets or nozzles are provided in a concentric arrangement around the burner opening. These air nozzles are connected with the main air passage by conduits, and the air stream discharging from the air nozzles is regulated by a flap.