A method of manufacturing a wiring substrate is disclosed. The method includes: (a) preparing a supporting substrate including a main body and a through electrode penetrating the main body, wherein the supporting substrate includes a first surface and a second surface opposite to the first surface, and a trace is formed on the second surface of the supporting substrate; (b) forming a build-up wiring structure by alternately forming a wiring layer and an insulating layer on the first surface of the supporting substrate; and (c) obtaining a wiring substrate by separating the build-up wiring structure from the supporting substrate. Step (b) includes: forming the wiring layer using the through electrode as a power feeding wiring, and step (c) includes: peeling the build-up wiring structure from the supporting substrate to obtain the wiring substrate.