A resin composition includes (A) a polyolefin epoxy resin, (B) an epoxy resin having a condensed polycyclic aromatic hydrocarbon, (C) a nitrogen-containing novolak resin, and (D) an inorganic filler, in which an epoxy equivalent of the (A) component is 200 g/eq. or more, a nitrogen content in the (C) component is 13% by mass or more and/or the (C) component has a cresol novolak structure, and a content of the (D) component is 60% by mass or more on the basis of 100% by mass of non-volatile components in the resin composition.