A method of manufacturing an electronic-component-embedded substrate includes forming a power-supplying metal layer on a base, forming through electrodes that are to be connected to the power-supplying metal layer on the power-supplying metal layer by an electrolytic plating method, forming a first wiring line by patterning the power-supplying metal layer, forming an interlayer insulating layer such that the interlayer insulating layer covers a portion of the first wiring line, and forming a second wiring line on at least a portion of the first wiring line and a portion of the interlayer insulating layer such that the second wiring line crosses, on the interlayer insulating layer, a portion of the first wiring line.