NOVELTY - A composition comprises (meth)acrylate compound (A), (meth)acrylate compound having more than 6C ester-bonded alicyclic hydrocarbon group (B), component (C) containing (meth)acrylic acid, or (meth)acrylate compound having polar group, radical polymerization initiator (D), and component (E) containing silica-type fine-particles, or silica-type fiber having average fiber diameter and fiber length of 0.1-500 mu m. The content of component (E) is 5-500 parts mass with respect to 100 parts mass of component (A), (B) and (C).    USE - Composition is used for cured material used as raw material for sealing material for light emitting element in optical semiconductor device and light receiving element (claimed). Uses include but are not limited to light emitting diode chip, semiconductor laser, photodiode, photo-interrupter, photocoupler, photo-transistor, electroluminescent element, charge-coupled device and solar cell.    ADVANTAGE - The composition has favorable heat resistance and adhesiveness. The cured material containing composition can easily scatter the light emitted by optical-semiconductor element. The generation of disconnection defect of the gold wire during thermal shock test is suppressed.    DETAILED DESCRIPTION - A composition comprises (meth)acrylate compound (A), (meth)acrylate compound having more than 6C ester-bonded alicyclic hydrocarbon group (B), component (C) containing (meth)acrylic acid, or (meth)acrylate compound having polar group, radical polymerization initiator (D), and component (E) containing silica-type fine-particles having average particle diameter of 0.1-500 mu m, or silica-type fiber having average fiber diameter and fiber length of 0.1-500 mu m. The content of component (E) is 5-500 parts mass with respect to 100 parts mass of component (A), (B) and (C). The (meth)acrylate compound (A) is chosen from alkyl (meth)acrylate having more than 12C alkyl group, polyalkylene glycol (meth)acrylate having number average molecular weight of 400 or more, and (meth)acrylate-modified silicone oil. INDEPENDENT CLAIMS are included for the following:    (1) cured material, which is obtained by curing the composition; and    (2) sealing material.