The present invention provides a disk drive device that can appropriately clamp a disk by means of magnetic force even when the disk drive device is very small. A clamping magnet 16 on which a disk 20 is mounted is attached to a turntable portion 15b of a rotor frame 15 to attract the disk 20. The clamping magnet 16 is configured so that the disk 20 can be mounted on the clamping magnet 16. An area of the rotor frame 15 from the turntable portion 15b to a boss portion 15a is composed of a ferromagnetic material.
