PURPOSE: To obtain the subject calibrated fine particles excellent in stability and having no chemical toxity by recovering liquid droplets formed from a collagen acidic soln. within a neutral or basic buffer aq. soln. and immediately polymerizing and coagulating them to form particles and separating the particles to wash them.

CONSTITUTION: For example, preliminarily properly oxidized dextran or cellulose is mixed with a cow collagen aq. soln. and a periodic acid soln. is added to the resulting mixture up to a range of 10-1-10-4 M to apply oxidizing treatment thereto and the oxidized mixture is introduced into a closed tank 1 and compressed air is sent to the mixture. The pressurized collagen soln. is passed through a pipe 4 having a capillary tube provided to the outlet part thereof to receive vibration in the capillary tube part and a collagen bond is cut to become spherical particles having a constant particle size of 50 μm-2 mm on an average and these particles enter a container 9 housing a basic buffer soln. These particles are recovered by filtering to be washed with distilled water to obtain the objective fine particles. A substance constituting an effective main component is dissolved in the collagen soln. to be finely divided to obtain a product such as a hemostatic powder or cosmetics.