Embodiments of the invention provide a magnetic disk device which improves the shielding function for the magnetic heads while maintaining a form factor having an inexpensive constitution. In one embodiment, a magnetic disk device comprises a rotary disk-type magnetic disk; a magnetic head for recording or reproducing information; a magnetic head support mechanism for supporting the magnetic head; a shroud having an opening in which the magnetic head support mechanism is inserted, and surrounding the outer circumference of the magnetic disk; and a housing. The housing includes a base and a cover, and accommodates the magnetic disk, the magnetic head, the magnetic head support mechanism and the shroud. The base is constituted by using a nonmagnetic material and the shroud is constituted by using a magnetic material.