A polymer composite material provides superior heat resistance, mechanical physical properties, substance permeation barrier properties, flame retardant properties, electrical conductivity and the like. Moreover, a novel surface-modified nanofiller utilizes this type of polymer composite material. The polymer composite material contains nanofillers, fluorocompounds and polymers. Fluoruocompounds bond to the surface of the nanofillers. The nanofillers to which fluorocompounds are surface-bonded are mixed with or dispersed in polymers.