PROBLEM TO BE SOLVED: To provide a nanocarbon polymer composite in which the surface of nanocarbon is completely coated with a polymer, and the coating polymer is hardly eliminated and to provide a production method thereof.SOLUTION: A polymer coating formed by thermally polymerizing a monomer on the surface of nanocarbon is generated by dispersing nanocarbon into a thermally polymerizable monomer or a solution of the thermally polymerizable monomer, and by irradiating light to the nanocarbon dispersion into which a polymerization initiator and/or a thermal polymerization catalyst are added, as the need arises.