An epoxy resin cured article has a high glass transition temperature and low dissipation factor. An epoxy resin composition from which the cured article can be having excellent solubility in solvents is used to produce the cured articles. A polyester as a curing agent of an epoxy resin composition having an aromatic polyhydroxy coumpound residue including an aryloxycarbonyl group at the molecule of the terminal, an aromatic polyvalent hydrocarbon group residue, and bulky structure, is used. Since the curing agent behaves as a polyfunctional curing agent, a cured article produced therefrom has a high crosslink density. Since highly polar hydroxyl groups are not formed during curing, a cured article has high glass transition temperature and a low dissipation factor. The cured article does not release low molecular weight carboxylic acids though hydrolysis of ester bonds at crosslinked bonds. Since the polyester has a bulky structure, the crystallization of the molecular chain is prevented and the solubility of the epoxy resin composition containing the polyester is excellent.