A coil assembly of a disk device includes a support frame on which a voice coil is fixed and a board unit connected to the support frame. The board unit has a main FPC extending from a base portion and a connecting portion extending from one side of an extended end portion of the main FPC. The connecting portion comprises a first connecting portion which extends in a longitudinal direction of the main FPC and has a plurality of first connection pads, a junction portion extending from the first connecting portion, and a second connecting portion which extends in the longitudinal direction of the main FPC from the junction portion and has a plurality of second connection pads. The first and second connecting portions are fixed to first and second support surfaces, respectively, of the support frame.