To obtain a new polyepoxy compound that has excellent heat resistance and water resistance, and is useful as an adhesive, sealer, laminating resin, casting material, molding material, electric insulation material, etc., by reaction of a specific polyphenol compound with an epihalohydrin.

This new polyepoxy compound, which contains a trisepoxy shown by formula I (R is methyl; X is a 1-6C alkyl, alkoxy, or a halogen; Y is H or methyl; (m) and (n) are each an integer of 0-2), is useful as an adhesive, sealant, laminating resin, casting material, molding material, electric insulation material, etc., and is obtained by allowing a polyphenol compound of formula II to react with an epihalohydrin of formula III (T is a halogen), for example, epichlorohydrin, etc.) in isopropyl alcohol while dropping an alkali, such as aqueous 50% sodium hydroxide solution into the reaction mixture.