A method for preparing a resin particle having a large surface area and a shape factor (SF-1) of 110 to 800, which comprises a step of applying a shear force to an aqueous dispersion having a viscosity of 300 to 100,000 mPas formed by adding a thickener to an aqueous dispersion containing resin particles, and a subsequent step of decreasing the viscosity of the aqueous dispersion to 200 mPas or less by adding a viscosity decreasing agent as necessary. Resin particles obtained by the method can be used as additives for paint, additives for coating materials, powder coatings, additives for cosmetics, resins for slush molding, spacers for use in manufacturing electronic components or devices, standard particles for electronic measuring instruments, toners for electrophotography, toners for electrostatic recording, toners for electrostatic printing, and hot-melt adhesives.