A burner in which a premixed air-acetylene flame can be sandwiched with oxygen has been designed, and the atomic absorption analysis using this burner was examined. The flame temperature, the flame spectra and the analytical sensitivity were determined for samples both in aqueous solution and organic solvents. The maximum temperature of the flame of this burner was about 2900 °C. The flame spectra were different from those of air-acetylene flame and oxygen-acetylene flame. The ability for the chemical reduction in this burner was found to be higher than that of premixed air-acetylene flame. By the use of this burner, an enhancement of the analytical sensitivity was observed for those elements in aqueous solution, the monoxide dissociation energy value of which is about or above 4.5 eV. This burner was applied to atomic absorption analysis using organic sol-vents such as benzene, hexane, toluene, xylene or cyclohexane. The organic solvents were burnt satisfactorily, and the analytical sensitivities were enhanced to (220) times compared with those when aqueous solution was used. From the results, it is concluded that this new type burner is very useful for atomic-absorption work.