The present invention is to provide a curable resin composition that is desirably used for manufacturing an optical part, in particular, an optical
waveguide, that is superior in heat-resistant properties such as a heat-resistant decomposing property and a coloring-resistant property, and has its
refractive index precisely controlled. The present invention provides a curable resin composition, comprising: (A) a
monomer that contains a polycyclic alicyclic
hydrocarbon skeleton and two or more terminal radical polymerizable groups, (B) a
monomer that contains a perfluoroalkylene skeleton and two or more terminal radical polymerizable groups, and (C) a photopolymerization initiator and / or a thermal
polymerization initiator. The present also provides an optical part, in particular, an optical
waveguide, formed by photo-and / or thermo-curing the above curable resin composition.