To produce fine particles having high monodispersibility, wherein a solution containing a fine particle formation material is inhibited from being decomposed and deteriorated.

The method for producing fine particles using a solution L1 in which an organic pigment is dissolved in a solvent with a dissolution auxiliary having reactivity for the organic pigment includes the steps of: preparing the solution L1 by joining a good solvent containing the organic pigment and the dissolution auxiliary in one junction region via feed channels that are independent of each other; and continuously mixing the prepared solution L1 with a poor solvent L2 which changes the solubility of the organic pigment of the solution L1 to generate the fine particles.