The present invention relates to an adhesive having high adhesiveness to a metal, especially a noble metal and a noble metal alloy. This adhesive comprises a thiouracil derivative typified by 6-methacryloyloxyhexyl 2-thiouracil-5-carboxylate, a radical-polymerizable monomer such as 2,2-bis(4-(methacryloxyethoxy)phenyl)propane, and a polymerization initiator, and as required, a filler.