Provided are an insulated ultrafine powder obtained by adding liquid metal alkoxide to a methanol-containing organic solvent in which a conductive ultrafine powder comprising a carbon material is dispersed and further adding water thereto and a method for producing the same. Also, provided are an insulated ultrafine powder obtained by adding liquid metal alkoxide to a methanol-containing organic solvent in which a conductive ultrafine powder comprising a carbon material is dispersed, further adding a coupling agent having an alkoxide group and then adding water thereto and a method for producing the same. Further, provided is a high dielectric constant resin composite material obtained by blending the insulated ultrafine powder of the present invention with a resin in a volume ratio (insulated ultrafine powder/resin) falling in a range of 5/95 to 50/50.