An electronic device has a substrate, a conductive layer and a substrate mounted portion. The substrate has a circuit portion used from 60 GHz to 80 GHz. The conductive layer is provided directly on a face of the substrate that is opposite side of the circuit portion. The face having the circuit portion of the substrate is mounted face down on the substrate mounted portion. A thickness of the conductive layer is a thickness where a sheet resistance of the conductive layer is 1/4 to 4 times of a resistance component of an impedance of the substrate.