The present invention provides a non-ester type epoxy resin having a low hydrolytic chlorine content and containing no ester bond that is easily hydrolyzed, and a resin composition containing the non-ester type epoxy resin as an essential ingredient. Using the non-ester type epoxy resin, a resin composition having a low chlorine content and also having low water absorption and acid value is obtained. The resin composition is useful as a curable resin composition for a material in an electronics.