A single droplet experiment and a spray combustion experiment for kerosene/water emulsified fuel were carried out to investigate the characteristics of the secondary atomization and the spray combustion for the emulsified fuel. Moreover, numerical calculation of spray combustion of kerosene and the emulsified fuel without considering secondary atomization were carried out. In the single droplet experiment, a micro-explosion and a puffing were observed. While the average superheat temperature of the droplet just before the occurrence of the micro-explosion was 40 K, that just before the occurrence of the puffing was 25 K. It was shown that the superheat temperature was the dominant factor in determining the secondary atomization behavior. In the spray combustion experiment, gas temperature distribution became uniform when the emulsified fuel was used. The calculation results of kerosene were in good agreement with the experimental ones. However, the calculated results of the emulsified fuel were different from experimental ones because the secondary atomization was not considered in the calculation. From these results, it was shown that the secondary atomization had a significant effect on the combustion characteristics.