TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Composition: The component (B) is compound containing phenolic-hydroxyl group. The compound (A) comprises alicyclic epoxy compound or alkylphenol-type epoxy compound. The content of component (A) is 50-95 %mass with respect to the total content of component (A) and component (B). The content of component (C) is 10-300 parts mass with respect to 100 parts mass total content of component (A) and component (B). The silane coupling agent (E) is trialkoxysilane which has reactive functional group. The component (E) contains reactive functional group chosen from glycidyl group, acryloyl group, and methacryloyl group. The content of component (E) is 10-100 parts mass with respect to 100 parts mass component (C). The monofunctional (meth)acryl compound (G) contains glycidyl group. The component (G) is glycidyl methacrylate. The component (H) comprises peroxide and/or optical radical initiator. The core component of the optical wave guide comprises (meth)acryl compound. The optical radical initiator is bis(( eta )(5)cyclopentadienyl)-bis(2,6-difluoro-3-(pyrrol-1-yl)phenyl)titanium.    TECHNOLOGY FOCUS - POLYMERS - Preferred Composition: The resin composition further comprises component (D) containing silicone oil, component (E) containing silane coupling agent, (meth)acrylic polymer (F), monofunctional (meth)acryl compound (G), radical initiator (H). The component (A) is hydrogenated-bisphenol-A-type epoxy resin. The component (B) is amino triazine novolak resin. The silicone oil contains glycidyl group in both terminal. The content of component (D) is 1-30 parts mass with respect to 100 parts mass total content of component (A) and component (B). The (meth)acrylic polymer (F) comprises 10-80 %mass glycidyl (meth)acrylate (F-1), and 20-90 %mass alkyl (meth)acrylate (F-2) containing 1-6C alkyl with respect to 100 %mass (meth)acrylic polymer (F). The content of component (F) is 1-40 parts mass with respect to 100 parts mass total content of component (A) and component (B). The base material of the resin film is chosen from polyethylene terephthalate, polyethylene naphthalate, copper foil, and copper foil with a carrier. The resin film further comprises protective film which covers the surface in opposite side to the near surface in which the base material of the resin composition layer is provided. Preferred Properties: The mean molecular weight of component (D) is 700 or less. The hardened material obtained using the resin composition has thickness of 50 mu m, and light transmittance of 95% or more in wavelength of 850 nm.