A component-incorporated wiring substrate is provided. Some embodiments include a plate-like component incorporated in a core substrate and a build-up layer having an insulation layer and a conductor layer disposed in alternating layers. The component has terminal electrodes formed at its opposite ends having a side surface and a main surface. An insulation layer disposed on the main surface of the component has via conductors formed therein which are connected to the side surfaces and the main surfaces of the respective terminal electrodes. The via conductors are tapered, such that their via diameter decreases in a direction toward the terminal electrode, and their via diameter at a position where they connect to the main surface is greater than a length of the main surface. Accordingly, the area of connection between the via conductors and the corresponding terminal electrodes is increased, improving connection reliability through enhancement of tolerance for positional deviation.