Abstract: In a premix burner, the swirl-stabilized interior space (18) has a conical inner body (13) running in the direction of flow. The outer casing of the interior space (18) is pierced by tangentially arranged air-inlet ducts (11a, 12a) through which a combustion-air flow (16) flows into the interior space (18). The swirl flow (23) forming in the interior space (18) is enriched with a fuel via at least one fuel lance (17). The mixture of the two media is then formed in the downstream mixing tube (21). The mixing tube (21) then merges into a combustion space (31) via a jump in cross section, a backflow zone (32) forming in the region of the plane of the jump in cross section, which backflow zone (32) ensures the stability of the combustion.