There is provided an organosol of surface-modified fluoride colloid particles obtained by coating the surface of a fluoride colloid particle as a core with an organophosphorus compound and a method for producing the organosol. An organosol of a surface-modified fluoride colloid particle comprising: a fluoride colloid particle as a core; and at least one type of an organophosphorus compound selected from a group consisting of organophosphorus compounds represented by the following general formulae (1), (2), and (3): (R--O).sub.nP(.dbd.O)(OM).sub.3-n (1) (R--O).sub.nP(OM).sub.3-n (2) (R).sub.nP(.dbd.O)(OM).sub.3-n (3) where R represents a substituted or unsubstituted alkyl group, alkenyl group or aryl group, M represents a hydrogen atom, an alkali metal or NZ.sub.4 (Z represents a hydrogen atom or an alkyl group); and n represents an integer of 1 or 2, the organophosphorus compound coating a surface of the fluoride colloid particle.