There are disclosed insulated ultrafine powder comprising
electroconductive ultrafine powder which is in the form of sphere,
spheroid or acicular each having a minor axis in the range of 1 to 100 nm
and an insulating film applied thereto; a process for producing the same
which is capable of covering the surfaces of the insulated ultrafine
powder with the insulating film having a thickness in the range of 0.3 to
100 nm without causing any clearance or vacancy; and a resin composite
material which uses the same. A high dielectric constant of the material
is assured by adding a small amount of insulated ultrafine powder wherein
an insulating film is applied to the electroconductive ultrafine powder,
while maintaining the processability and moldability that are the
characteristics inherent in a resin material.