The present invention provides a resin composition which enables to obtain a transparent member having excellent transparency, high refractive index and high strength and an optical component composed of such a transparent member. A resin composition of the present invention comprises a polymerizable compound or a resin component and an organically modified fine particle produced in the presence of a high-temperature high-pressure water as a reaction field, in which an organic material is bonded to the surface of a metal fine particle.