A wiring board includes a substrate, a first conductor layer, a second conductor layer, and a through-via conductor. The substrate has a first surface, a second surface, and at least one through-via. The first conductor layer is formed on the first surface, and the second conductor layer is formed on the second surface. The through-via conductor is formed in the through-via for electrically connecting to the first conductor layer and the second conductor layer. The through-via has a first depressed portion exposed in the first surface, a second depressed portion exposed in the second surface, and a tunnel portion between the first depressed portion and the second depressed portion for connecting the first depressed portion and the second depressed portion. The first depressed portion and the second depressed, portion are non-coaxial.