To achieve high-speed thick film synthesis or to obtain a large volume of super fine particles.

A vessel 25A with solvent stored therein, vessels 25B, 25C and 25D with single phase solutions different from each other stored therein, and valves 26A, 26B, 26C and 26D for controlling the flow rates of the solutions from the vessels are provided. Output line tubes of the valves are collected in one place and integrated with each other. A buffer 20, a pump 28 and a mixer 29 are disposed in this order in the middle of the integrated line tube with spaces therebetween. By controlling the opening/closing degree of each valve, the composition ratio and concentration of the liquid mixture can be adjusted, and each solution is sucked and discharged by the pump 28. Each solution is mixed by the mixer 29 so that the liquid mixture is sprayed into a torch 1 from a nozzle-like tip of a tube 51 for introducing spray gas.