Provided is a substrate with built-in electronic component including a component storage layer and two buildup layers. The component storage layer includes an electronic component and a cover portion having an insulating property. The electronic component includes a terminal surface and a main body. The cover portion includes a first surface formed to be flush with the terminal surface, covers the main body of the electronic component, and has a first linear expansion coefficient. The two buildup layers each include an insulating layer and a via portion. The insulating layer is adjacent to the cover portion and has a second linear expansion coefficient larger than the first linear expansion coefficient. The via portion is provided in the insulating layer and connected to the terminal surface. The insulating layer of one of the two buildup layers is formed to be in contact with the terminal surface and the first surface.