PURPOSE: To obtain a floppy disk device, which conducts clamping operation smoothly by preventing the biting of a magnetic disk.

CONSTITUTION: A sleeve 39 supported on a collet 20 is put aside to the central side of a pivotal motion and supported in the support hole 38 of a lifter 12 by a torsion coil spring 30. The collet 20 is positioned correctly into the center hole 6d of a magnetic disk 6 by the energizing force of the torsion coil spring 30 when the magnetic disk 6 is clamped. The collet 20 is moved in the support hole 38 of the lifter 12 against the energizing force of the torsion coil spring 30, and placed correctly to a spindle 10, thus clamping the magnetic disk 6.