PROBLEM TO BE SOLVED: To provide a cross-linked polyacrylonitrile-based fine particle having minute irregularities on the surface, which can attain, in spite of a spherical shape, both surface characteristics depending on the irregularities on the particle surface and good handling properties when used alone or when mixed with the other material, and to provide a method for producing the fine particle.SOLUTION: The cross-linked polyacrylonitrile-based fine particle having fine irregularities on the surface has a circularity of 0.97 or more, a specific surface area of 0.8-5.0 m/g and an average particle size of 5-100 μm. The method for producing the fine particle includes: adding, to an aqueous solution of a water-soluble dispersion stabilizing agent, a vinyl monomer mixture including, as essential components, acrylonitrile in which an oil-soluble polymerization initiator is dissolved and a cross-linking vinyl monomer to make the mixture into fine droplets, and then adding the water-soluble dispersion stabi
