A circuit board includes a core layer including a plurality of metal layers laminated one over another, a bottommost metal layer of the plurality of metal layers being thickest, and a topmost metal layer of the plurality of metal layer being thinnest; an upper insulating layer and an upper conductive pattern provided over a top surface of the core layer; and a lower insulating layer and a lower conductive pattern provided below a bottom surface of the core layer, wherein the topmost metal layer of the core metal layer is patterned to have a prescribed shaped section that serves as wiring and that is connected to the upper conductive pattern, wherein a metal ratio that is defined as a ratio of an area that is formed of metal relative to an entire area in a plan view is higher in the bottommost metal layer than in the topmost metal layer.