An apparatus for forming ultrafine particles, including: a light source generating a laser beam to be irradiated at an organic substance; at least one microflow channel capable of passing therethrough a suspension containing the organic substance; and a flow device for allowing the suspension containing (the organic substance to continuously or intermittently pass through the microflow channel, the organic substance present in the microflow channel being irradiated with the laser beam at least once within a predetermined period, thereby forming ultrafine particles of the organic substance.
