A coil device includes a base, a cover facing the base and forming a receiving space between the base and the cover, a casing disposed inside the receiving space and containing a coil therein, a substrate disposed inside the receiving space and having a through hole passing through the substrate along a facing direction of the base and the cover, and a support portion disposed in the through hole, wherein the support portion has a strength greater than a strength of the substrate and wherein the support portion has a height greater than a thickness of the substrate.