The invention relates to a resin composition which is characterized by including: a reaction product that includes (A) a polyphenylene ether having an average of 1.5 to 2 hydroxyl groups per molecule and (B) an epoxy compound having an average of 2 to 2.3 epoxy groups per molecule, wherein the reaction product is obtained by pre-reacting at least a part of hydroxyl groups on the polyphenylene ether (A) with epoxy groups on the epoxy compound (B) so that the concentration of terminal hydroxyl groups on the polyphenylene ether (A) becomes 700 μmol/g or less; (C) a cyanate ester compound; and (D) an organometallic salt.