Curable composition, cured product, optical member, lens, and method for producing cured product

A curable composition comprising:

• a cardo skeleton-containing monomer having two or more (meth)acryloyl groups in a molecule;
• an aromatic ring-containing monofunctional (meth)acrylate monomer;
• a polymer having a radically polymerizable group in a side chain;
• and
• an acidic phosphate ester,
• wherein the content of the cardo skeleton-containing monomer is 30% to 90% by mass with respect to the total mass of the curable composition,
• the content of the polymer is from greater than 0% to 40% by mass with respect to the total mass of the curable composition,
• the acidic phosphate ester is a compound represented by General Formula (1), and
• the content of the acidic phosphate ester is 0.003% to 1% by mass with respect to a total mass of the curable composition;
• in General Formula (1), R1 and R2 may be the same as or different from each other and each independently represent a hydrogen atom or an alkyl group which may have a substituent;
• and at least one selected from R1 or R2 is an alkyl group which may have a substituent.