A circuit board according to an embodiment includes: a first insulation layer, a first circuit wire that is disposed on the first insulation layer, a second insulation layer that covers the first insulation layer and the first circuit wire, and includes a material that is different from that of the first insulation layer, and a third insulation layer that is disposed on the second insulation layer and includes a cavity. A bottom surface of the cavity is a top surface of the second insulation layer.