A printed-wiring substrate 1 includes internal dielectric resin layers 12 and 14. A main-surface-side external dielectric resin layer 13 is formed on the internal dielectric resin layer 12 such that the surface thereof serves as a substrate main-surface 1A. A back-surface-side external dielectric resin layer 15 is formed on the internal dielectric resin layer 14 such that the surface thereof serves as a substrate back-surface 1B. A surface 12A of the main-surface-side internal dielectric resin layer 12 and a surface 14A of the back-surface-side internal dielectric resin layer 14 are roughened. The substrate main-surface 1A and the substrate back-surface 1B are roughened such that surface roughness thereof is lower than that of the surfaces 12A and 14A.