A disk drive (10) includes a plurality of thin-film members (36) for respectively covering the desired contour portions in a plurality of suspension arms (26) of an actuator (20). Each thin-film member (36) is fixedly attached to the surface of the suspension arm to cover the contour portion around a through hole (34) formed in the corresponding suspension arm (26) for reducing the moment of inertia, so as to cover the through hole. The thin-film member (36) substantially makes the contour portion around the through hole of the suspension arm (26) flush, and the air flow caused around the storage disks (16) rotating at high speed is guided smoothly along this contour portion. As a result, the air flow is stabilized, and the influences such as vibration on the actuator (20) are suppressed.