Resin composition, resin sheet, resin sheet with metal foil, hardened resin sheet, structure, and semiconductor device for power or light source

This resin composition contains an epoxy resin containing a multifunctional epoxy resin, a curing agent containing a novolac resin having a structural unit represented by general formula (I), and an inorganic filler containing nitride particles. In general formula (I): R1 and R2 each independently represent a hydrogen atom or a methyl group; m has an average value of 1.5 to 2.5; and n has an average value of 1 to 15.