A coil device comprising; a winding coil including Cu and having a winding part and an extension line part which is pulled out from said winding part, a pair of electrodes made of a conductive material having, a connecting wire part having a connecting wire face connected with the extension line part and a protective face sandwiching said extension line part with said connecting wire face, and a base part provided with a mounting base face at one of the faces of the base and connected to said connecting wire part, a magnetic part including a magnetic material and covering at least said winding part and said connecting wire part.