Organosilicon fine particles with polysiloxane network structure made of siloxane units of specified kinds at specified ratios and having a circular ring shape as a whole and average outer and inner diameters within specified ranges such that their difference is also within a specified range can provide antireflection and antiblocking characteristics to synthetic polymer films and sheets when applied to their surface or caused to be contained, respectively, and adherence and slip characteristics to a skin care cosmetic material when caused to be contained.