In a circuit board, a laminate includes a plurality of laminated insulating material layers made of a flexible material. First external electrodes are provided on an upper surface of the laminate, and an electronic component is mounted thereon. Second external electrodes are provided on a lower surface of the laminate and mounted on a wiring board. An internal conductor is provided between first and second adjacent insulating material layers, fixed to the first insulating material layer, and not fixed to the second insulating material layer. The internal conductor is arranged so as to extend across regions obtained by connecting certain ones of the second external electrodes to certain ones of the first external electrodes located closest to the certain ones of the second external electrodes.