[Object] A curable epoxy resin composition is provided which is excellent in toughness, is hardly fractured, is strongly adhered to another material, and is also excellent in weather resistance, chemical resistance, and the like while maintaining excellent heat resistance, elastic modulus, and the like inherent to an epoxy resin.[Solution] A curable resin composition contains, with respect to 100 parts of an epoxy resin, 1 to 70 pars of an epoxy resin curing agent and 1 to 50 parts of an acrylic block copolymer, and the acrylic block copolymer contains (α) at least one polymer block A composed of a structural unit derived from an alkyl methacrylate and at least one polymer block B composed of a structural unit derived from an alkyl acrylate, has a weight average molecular weight (Mw) of 30,000 to 300,000 and a molecular weight distribution (Mw/Mn) of 1.5 or less, and contains 3 to 60 percent by mass of the polymer block A. In addition, a cured resin is formed from the above curable resin composition.