A stack package includes a core layer having a first surface and a second surface, and including first circuit wiring lines; a first semiconductor device disposed on the second surface of the core layer; a first resin layer formed on the second surface of the core layer to cover the first semiconductor device; second circuit wiring lines formed on the first resin layer and electrically connected with the first semiconductor device; a second semiconductor device disposed over the first resin layer including the second circuit wiring lines and electrically connected with the second circuit wiring lines; a second resin layer formed on the second circuit wiring lines and the first resin layer to cover the second semiconductor device; and a plurality of via patterns formed to pass through the first resin layer and the core layer and electrically connecting the first circuit wiring lines and the second circuit wiring lines.