A curable composition containing a radical-polymerizable monomer and a hard solid component having a volume average particle diameter of 10 nm or greater and 1,000 nm or less is provided. The content of the hard solid component is 3% by volume or greater and 40% by volume or less. The difference (n1−n2) between the refractive index (n1) of a cured product of any other component than the hard solid component and the refractive index (n2) of the hard solid component is 0.04 or greater.