To develop combustion technology for upgrading the quality of fly ash, the influences of the coal properties, Such as the size of pulverized coal particles and the two-stage combustion ratio during the combustion, oil the fly ash properties were investigated using Our test furnace. The particle size, density, specific surface area (obtained by the Blaine method), and shape of fly ash particles of seven types of coal were measured, It was confirmed that the size of pulverized coal particles affects the size of the ash particles. Regarding the coal properties, the fuel ratio affected the ash particle size distribution. The density and shape of the ash particles strongly depended on their ash size. Our results indicated that the shape of the ash particles and the concentration of unburned carbon affected the specific surface area. The influence of the two-stage combustion ratio was limited.