We have developed a pyrolysis-based soot-generating system, which is able to control the primary soot particle size. The system is clean and portable and runs On diverse hydrocarbon fuels of interest. To evaluate the performance of the system, soot was generated from n-hexane and propylene with various conditions of the temperature, fuel mole fraction, and residence time in the heating zone. The results showed that the primary soot particle size was controllable within the range of 20-60 nm, and the soot yield as a function of the residence time followed a logistic curve of different shape depending upon the fuel mole fraction and healing temperature. The system that we developed can be used as a reliable soot-generating source for diverse laboratories to meet the growing demands for fundamental research on soot characteristics and soot formation mechanisms as well as the assessment of health and environmental effects of soot from various sources.