Abstract: Provided are a halogen-free and phosphorus-free prepreg having good flame retardancy and having excellent electric characteristics and heat resistance, and a laminated board. The prepreg is formed of a resin composition comprising, as essential components, a phenol compound (I) having a structural unit of the formula (1), wherein R1 is hydrogen or phenol, R2 is a hydrogen or methyl and n is an integer of 0 to 10, an epoxy resin (II) prepared by epoxidizing the same phenol compound as said phenol compound, a metal hydrate (III) and a molybdenum compound (IV), and a substrate which is impregnated with said resin composition or to which said resin composition is applied. The laminated board for an insulating material, which is formed of the prepreg.