Voice coil device and speaker device using the voice coil device

An example speaker device includes a vibration system having a frame, first and second voice coils, a voice coil bobbin, a diaphragm and a magnetic circuit holder, and a magnetic circuit system having a yoke, a magnet and first and second plates. The first and second voice coils are wound around the voice coil bobbin with a constant space. The diaphragm has a step portion having an upper surface ensuring flatness at an inner peripheral portion (neck) thereof. An inner peripheral edge portion of the diaphragm is fixed to the voice coil bobbin. The first plate, the magnet and the second plate are fixed onto a pole portion of the frame in an upward order, respectively. The annular yoke is mounted onto a predetermined position of the magnetic circuit holder formed into a mushroom shape, and the magnetic circuit holder is fixed onto the second plate via a bolt. Thereby, the first and second magnetic gaps are formed in the vicinity of the first and second voice coils, respectively.