It is an object of the invention to provide a rubbery polymer-containing resin composition useful as a raw material for a molded article and a cured product having high transparency and excellent mechanical strength: namely, an object of the invention is to provide, for example, a cycloaliphatic epoxy resin composition capable of improving the toughness thereof while maintaining the mechanical strength and transparency of the cycloaliphatic epoxy resin without lowering the heat resistance, a production method thereof and a cured product thereof. A rubbery polymer-containing resin composition of the invention, for example, a cycloaliphatic epoxy resin composition of the invention is a cycloaliphatic epoxy resin composition comprising 100 parts by weight of a cycloaliphatic epoxy resin and 1 to 60 parts by weight of polymer particles with a volume average particle diameter (Mv) of not smaller than 0.01 μm and not larger than 0.5 μm, characterized in that each of the polymer particles comprises at least two layers of an elastic core layer present in the inside thereof and a shell layer present in the outermost side thereof, the elastic core layer consisting of a rubbery polymer with a glass transition temperature of lower than 10° C., and the composition is colorless and transparent.