Abstract: The present invention provides a zirconium element-containing resin composition capable of achieving both high transparency and a high refractive index. The present invention is a zirconium element-containing resin composition containing a zirconium element-containing metal oxide (A); a dispersant (B); and a polymerizable resin (C), in which the zirconium element-containing metal oxide (A) has an average particle diameter of 20 nm or less as measured by a dynamic light scattering method, and the dispersant (B) contains a compound represented by the following formula (1), the zirconium element-containing resin composition may contain a silane coupling agent, and a content ratio of the silane coupling agent is less than 30 parts by mass with respect to 100 parts by mass of a total of the compound represented by the formula (1) and the silane coupling agent.

Abstract: The present invention provides a resin composition which has excellent handleability and which provides a cured product having excellent toughness and heat resistance. The present invention relates to a thermosetting resin composition including an allyl compound (A) containing at least two or more allyl groups and one or more benzene rings in a molecule, a maleimide compound (B) containing at least two or more maleimide groups in a molecule, a thiol compound (C) containing at least two or more thiol groups in a molecule, and a cyclic compound (D) containing at least two or more hydroxyl groups in a molecule.