A three-dimensional circuit board includes a lower substrate, a connection layer provided on an upper surface of the lower substrate, and an upper substrate provided on an upper surface of the connection layer. The connection layer exposes a portion of the upper surface of the lower substrate. The connection layer includes an insulating layer having a through-hole, and a via-conductor made of conductive material filling the through-hole. A recess is provided directly above the portion of the upper surface of the lower substrate and is surrounded by a side surface of the upper substrate and a side surface of the connection layer. A portion of the upper surface of the connection layer connected to the side surface of the connection layer inclines in a direction toward the portion of the upper surface of the lower substrate. The portion of the upper surface of the connection layer is provided from the side surface of the connection layer to the via-conductor. A portion of an upper substrate of the upper substrate connected to the side surface of the upper substrate inclines in a direction toward the portion of the upper surface of the lower substrate. The circuit board allows a component to be mounted in the recess efficiently.