The stilbene epoxy resin having two different aryl groups and an epoxy resin mixture including this stilbene epoxy resin have lower melting points than those of the stilbene epoxy resin having two identical aryl groups and the epoxy resin mixture of the latter stilbene epoxy resin. Compared with the conventional resins, the present resin or resin mixture has improved working and molding properties, which shortens the time required for the molding and working process, resulting in economic advantages and a preferred affect on productivity. The present epoxy resin or resin mixture is preferably used as an adhesive, a coating, an insulating material, an electrical or electronic material for laminated sheets or the like. It is especially suited for use as material for encapsulating electronic parts.