A spindle motor structure includes a solenoid coil 1 provided above a flexible board 2 provided at one face of a base plate of FDD to align in a circumferential direction centering on one axis and a turn table covering the solenoid coil 1 and provided rotatably centering on the one axis. The spindle motor structure can provide FDD capable of achieving a reduction in cost by reducing a number of parts of PWB and the like using a silicon steel plate, i.e. silicon steel plate PWB.