Abstract: The present invention provides a method for manufacturing a dispersion in which a substance, which is poorly soluble in a dispersion medium, is dispersed with a particle size of a nano-order level. More particularly, the method includes: preparing a solution containing a good solvent and the poorly soluble substance and the surfactant dissolved in the good solvent; rapidly cooling the solution to a temperature at which the poorly soluble substance precipitates in the solution at a temperature lowering rate of 100 to 4,000° C./second to produce ultrafine particles with a particle size of a nano-order level formed of the poorly soluble substance in the good solvent; and (i) separating the good solvent from a mixed solution of the solution and the dispersion medium after mixing the solution and the dispersion medium, or (ii) mixing the dispersion medium to the solution after separating the good solvent from the solution.