Abstract: A coil device includes: a bobbin having a winding core portion with a hollow cylindrical shape; a core at least partially disposed inside the winding core portion; a wire having a coil portion wound around the winding core portion and a lead portion having a wire connection portion led out from the coil portion to extend substantially parallel to a winding axis O of the coil portion; and a terminal portion having a connection portion connected to the wire at the wire connection portion. A connection portion inner end, which is a position closest to the winding axis in an X-axis direction perpendicular to the winding axis O, of contact portions of the wire connection portion in the connection portion is disposed closer to the winding axis O in the X-axis direction than a first outer end portion located at a position farthest from the winding axis O in the X-axis direction in the bobbin.