Provided is a wiring structure and the like which can completely connect a wiring layer to a body to be wired while keeping insulation between two adjacent wiring layers and realize high density packaging due to a narrowed pitch.In a semiconductor-embedded substrate, a conductive pattern is formed on both sides of a core substrate and a semiconductor device is placed in a resin layer stacked over the core substrate. The resin layer has via-holes so that the conductive pattern and a bump of the semiconductor device protrude from the resin layer. Inside the via-holes, the bump and conductive pattern are respectively connected to via-hole electrode portions whose cross-sectional area has been increased toward the bottom of the via-hole. A void is defined between the via-hole electrode portion and upper portion of the inner wall of the via-hole.