NOVELTY - An active-energy-ray-curable composition contains acrylic polymer, radical photopolymerization initiator, methacrylate monomer and epoxy group-containing compound. The content of methacrylate monomer and epoxy group-containing compound is 1-70 pts. wt. and 0.1-30 pts. wt. with respect to 100 pts. wt. acrylic polymer. The acrylic polymer has (meth)acryloyl group in a molecule, and is obtained by living radical polymerization.    USE - Active-energy-ray-curable composition is used for cured material for optical material and sealing material for manufacturing light-emitting diode module, solar cell module, flat panel display module, sensor module and lens module (all claimed). Uses include but are not limited to video camera, projection television, finder, still camera, touch panel, light guide, marker, waveguide, compact disk and optical cards.    ADVANTAGE - The active-energy-ray-curable composition has excellent storage stability, cold curing property, hardenability, and reduced viscosity and foaming property. The cured material of the composition has excellent heat resistance, light resistance, transparency, crack resistance, rubber physical property, moisture-proof permeability and designability.    DETAILED DESCRIPTION - An active-energy-ray-curable composition contains acrylic polymer, radical photopolymerization initiator, methacrylate monomer of formula: Rb-OC(O)C(CH3)=CH2, and epoxy group-containing compound. The content of methacrylate monomer and epoxy group-containing compound is 1-70 pts. wt. and 0.1-30 pts. wt. with respect to 100 pts. wt. acrylic polymer. The acrylic polymer has (meth)acryloyl group of formula: -OC(O)C(Ra)=CH2 in a molecule, and is obtained by living radical polymerization.    Ra=H or 1-20C organic group;and    Rb=6-20C organic group having alicyclic aliphatic structure or aliphatic branched structure.    INDEPENDENT CLAIMS are included for the following:    (1) cured material; and    (2) manufacture of light-emitting diode module, solar cell module, flat panel display module, sensor module and lens module.