To provide an organic-inorganic hybrid cured resin with high thermal decomposition temperature or glass transition temperature. An organic-inorganic hybrid cured resin is characterized by having a structure with inorganic nanoparticles dispersed in a thermosetting resin containing a triazine ring, and being transparent to visible light. The thermosetting resin is preferably a cyanate ester resin represented by a high-heat-resistance 2,2-Bis-(4-cyanatophenyl)propane, or a copolymer of a bismaleimide diphenylethane and a 2,2-Bis-(4-cyanatophenyl)propane. The inorganic nanoparticles dispersed in the resin is composed of at least one kind of metal oxide particles of silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide. Particle size of the inorganic nanoparticle is preferably 1nm to 100nm for achieving a high specific surface area effect of the inorganic nanoparticle. Accordingly, the present invention can provide an organic-inorganic hybrid cured resin which has high thermal decomposition temperature or glass transition temperature, and low hardening temperature.
