TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The silica fine particles (a) are obtainable by subjecting 100 parts by mass of the silica fine particle (a1) to a surface treatment with 5-100 parts by mass of the silane compound (d) and 100 parts by mass of the silica fine particle (a1) to a surface treatment with 5-100 parts by mass of the silane compound (e).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The polymerizable compound (b) comprises a (meth) acrylate compound (b3) having at least one (meth) acryloyloxy group and having no ring structure. The (meth) acrylate compound (b1) is a (meth) acrylate compound (b1a) having formula Y1-(O-C(=O)-C(R8)=CH2)h (III). The (meth) allyl compound (b2) is a (meth) allyl compound (b2a) having formula Z'-(C(=O)-O-CH2-C(R11)=CH2)h (V), or Z2-(O-C(=O)p-(CH2)o-C(R14)=CH2)n (X). The (meth) acrylate compound (b3) is a (meth) acrylate compound (b3a) having at least 2 (meth) acryloyloxy groups and having no ring structure.Y1, Z' and Z2=organic group having an aromatic ring structure with 6-18 carbon atoms;R8, R11 and R14=H or methyl;h, k and n=1-4;o=1-5;p=0 or 1.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The composition comprises 1-1000 parts by mass of the (meth)allyl compound (b2) per 100 parts by mass of the silica fine particles (a1); or totally 1-4000 parts by mass of the (meth) acrylate compounds (b1) and (b3) per 100 parts by mass of the silica fine particles (a1). EXAMPLE - SNOWTEX IPA-ST (RTM: colloidal silica dispersed in isopropyl alcohol) having silica fine particle content of 30% by mass, and average particle diameter of 10-20 nm was used as silica fine particle (a1), to be subjected to a surface treatment. To a separable flask, 100 parts (the amount including the solvent) of the colloidal silica dispersed in isopropyl alcohol were added; to the separable flask, 3 parts of gamma -methacryloyloxy octyltrimethoxysilane (MOS) and 9 parts of phenyltrimethoxysilane were added and mixed by stirring, and 3.9 parts of hydrochloric acid having a concentration of 0.1825% by mass were further added and the mixture was stirred at 25 degrees C for 24 hours; and thus the surface treatment of the silica fine particle (a1) was carried out and then a dispersion containing the surface-modified silica fine particle (A-1) was obtained. KAYARAD (RTM: trimethylolpropane triacrylate) (glass transition temperature (Tg) of the homopolymer of greater than 250 degrees C) (24 parts by mass) was added to 16 parts by mass of the surface-treated silica fine particle (A-1) and mixed uniformly. Then volatile components were removed by heating at 40 degrees C with stirring under a reduced pressure of 100 kPa. Subsequently, the obtained mother liquid was combined with 6:1 mixture of A-BPEF (RTM: 9,9-bis (4-(2-acryloyloxyethoxy) phenyl) fluorene) (60 parts by mass) and benzyl acrylate, FA-712HM (RTM: tetramethylpiperidyl methacrylate) (0.15 parts by mass) and Sumilizer GA-80 (RTM: 3,9-bis (2-(3-(3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy)-1,1-dimethylethyl)-2,4,8,10-tetraoxaspiro (5.5) undecane (0.15 parts by mass) and mixed uniformly. To 100 parts by mass of the obtained mixture, 0.15 parts by mass of PERBUTYL 0 (RTM: thermal polymerization initiator) was added to give a curable composition.