A surface-mounting substrate, for mounting thereon a part such as a semiconductor device, which comprises a core substrate, a plurality of layers of patterned wiring lines, which are separated from each other by an insulation layer interposed therebetween, vias piercing through the insulation layer to connect the wiring lines at the adjacent layers to each other, and a layer of connecting terminals to mount a part on the surface-mounting substrate, each of the connecting terminals connecting with the wiring line at the outermost layer of wiring lines, wherein the connecting terminal is filled in an outermost insulation layer provided at the surface of the surface-mounting substrate, and has a surface exposed at substantially the same level as the level of the surface of the outermost insulation layer. A structure comprising a surface-mounting substrate and a part mounted thereon, which comprises, as the substrate used, the surface-mounting substrate of the invention, is also disclosed.