Effects of axi-asymmetric combustion conditions were studied in a horizontally oil-fired and 3-staged swirl burner. Axi-asymmetric conditions were created by supplying combustion air through six different air inlets from the back panel of the burner. Experimental conditions were decided by varying the degree of axi-asymmetry and changing the location of the minimum flow rate value in unimodal and bimodal air distribution, Temperature profiles inside a furnace were mapped using R-type thermocouples and flame images were captured by a CCD camera, to investigate the intensity of visible flames, focusing on the effects of asymmetrically supplied combustion air. Experimental results show three distinct phenomena. The unimodal air distribution deformed the flame shape more axi-asymmetrically (inclined toward the minimum flow region) than the bimodal case. The flame shape was affected by buoyancy and by the location of the minimum flow rate in air distribution. Especially, when combustion air was discharged less in the ascending region of the swirl now, the name. shape was more deformed toward where the air was Supplied less. The critical values in the degree of axi-asymmetric combustion air supply were identified to form an inclined straight shape of the radial temperature profile rather than a parabolic one.