In this study, PM exhausted from unsteady pool flame of iso-octane on a shallow dish under various ambient temperature conditions (25 – 700°C) was investigated as fundamental study of fuel film combustion. Flame appearance from ignition to combustion end under various ambient temperature conditions was observed. Further, total masses of CO₂, CO and PM emitted from the flame during flame formation period were measured by gas analysis and filter method. In addition, the effect of lubricating oil addition in fuel on PM and combustion gas emitted from unsteady pool flame were investigated. As the result, it was found that total mass of CO₂ emitted during flame formation period decreased with ambient temperature rise, and total mass of CO and PM increased with ambient temperature rise. Moreover, it was found that the iso-octane with added lubricating oil (5wt%) emitted less CO₂ from the flame compared to the fuel without the lubricating oil addition.