Disk drive device rotationally driving recording disk

A disk drive device includes: a hub on which a recording disk is to be mounted; a base configured to rotatably support the hub via a bearing; a core that is fixed to the base and includes a circular portion and S salient poles (where S is a natural number greater than or equal to 3) extending from the circular portion in the diameter direction; a three-phase coil that is formed by being wound around each of the S salient poles; and a magnet that is fixed to the hub and faces the S salient poles in the diameter direction, and that is provided with P driving magnetic poles in the circumferential direction (where P is a natural number greater than or equal to 2). In the disk drive device, the fundamental frequency component of the cogging torque based on the LCM (Least Common Multiple) of S and P (where S is the number of the salient poles of the core and P is the number of the driving magnetic poles of the magnet), is smaller than the second frequency component of the cogging torque, the frequency of which is twice the fundamental frequency.