A method of manufacturing a circuit board includes forming a first electrode on a support substrate, covering the support substrate and the first electrode with a first insulating layer, polishing the first insulating layer to expose a first surface of the first electrode, forming a first wiring on the first insulating layer after exposing the first surface of the first electrode, the first wiring being connected to the first electrode, and removing the support substrate to expose a second surface of the first electrode after forming the first wiring.