Active-energy-ray-curable composition including: monofunctional monomers; and polymerization initiator, cured material of the composition satisfying 0.30≦D≦0.85, where D is difference between peak-area-ratios A and B in infrared-ATR and obtained by: the composition is coated on polycarbonate substrate to form coated film having average thickness of 10 μm; the film is irradiated with active energy rays having light quantity of 500 mJ/cm2 at UV intensity of 1.0 W/cm2 for curing; the A is obtained from Formula (1) by infrared-ATR at one portion present from the cured material surface through 1 μm away therefrom toward the substrate, the B is obtained from Formula (1) by infrared-ATR at one portion present from the substrate-cured material interface through 1 μm away therefrom toward the cured material surface, Peak-area (from 1,679 m−1 through 1,751 m−1/peak-area (from 1,096 m−1 through 1,130 m−1)  Formula (1), and the A and B obtained are used to obtain D from Formula (2): D=peak-area-ratio A−peak-area-ratio B  Formula (2).