A transparent composite composition is provided which is low in coefficient of linear expansion and excellent in transparency, heat resistance and solvent resistance and can serve as an optical sheet for a liquid crystal display device or organic EL display device, for instance and can thus serve as a glass substitute. The transparent composite composition has a transparent resin (a) and a glass filler (b), and the transparent resin (a) is a copolymer obtained from at least one reactive monomer lower in refractive index than the glass filler (b) and at least one reactive monomer higher in refractive index than the glass filler (b).