A hard disk drive according to an embodiment of the present invention includes a pivot assembly bearing device with a shaft, rolling bearings and a sleeve, a cylindrical convex portion formed in a cover member at the upper side, protruding inward, and fixed to an upper end surface of the shaft, a convex portion formed on a base member at the lower side, protruding inward, and fixed to a lower end surface of the shaft, and a labyrinth gap formed by opposing an outer peripheral surface of the convex portion to an inner peripheral surface of a sleeve in a radial direction and/or by opposing an outer peripheral surface of the convex portion to the inner peripheral surface of the sleeve in a radial direction.