Disclosed is a setting type resin composition comprising (A) a setting type resin and (B) 10 to 200 parts by weight, per 100 parts by weight of said resin (A), of a substantially linear, high-molecular-weight novolak type substituted phenolic resin which comprises a constituent phenol component comprised mainly of a bifunctional phenol and has a number average molecular weight of at least 1500. This resin composition has highly improved heat resistance and mechanical strength characteristics by virtue of incorporation of the high-molecular-weight novolak type substituted phenolic resin, and this improving effect is especially prominent when an epoxy resin is used as the setting type resin.