It is an object of the present invention to provide a method for producing microparticles, which can produce monodispersed microparticles, causes no clogging with a product due to self-dischargeability, requires no great pressure, and is excellent in productivity, wherein a fluid in which at least one kind of microparticle materials is dissolved is introduced between two processing surfaces arranged to be opposite to each other to be able to approach to and separate from each other, at least one of which rotates relative to the other, to be formed into a thin film fluid, and the thin film fluid is cooled or heated (warmed) to allow saturation solubility to change, thereby separating microparticles.