A method of molding a sandwich panel includes a step of providing, on one or both surfaces of an (a) core material, a prepreg or the prepreg and an adhesive as a (b) skin material. The (a) core material is a super engineering plastic foam having a glass transition temperature of greater than 200° C. The (b) skin material contains: a (b-1) epoxy resin having an average molecular weight of 1300 or more or having a trishydroxymethane-type or cresol novolac-type structure and containing, in a total epoxy resin, an amount of 70 to 100 mass % of an epoxy resin that is semi-solid or solid; a (b-2) epoxy resin containing, in the total epoxy resin, an amount of 0 to 30 mass % of an epoxy resin that is liquid; and a (b-3) curing agent.