A compact inexpensive optical disk drive adaptable to high-density optical disks is provided by improving a loading mechanism for an optical disk. A mechanism for loading an optical disk, in or from which information is optically recorded or reproduced, into the body of an optical disk drive is mounted on a chassis. The loading mechanism consists of a spindle motor, a lift plate, and a sheet loader. The spindle motor rotates an optical disk. The spindle motor is placed on the lift plate. The sheet loader moves the lift plate vertically to the chassis so as to attach or detach the spindle motor to or from the optical disk. In the storage device, the tilt of the lift plate relative to the chassis is adjusted at three points on the lift plate. Blade springs for constraining the lift plate to move towards the optical disk are interposed between the chassis and lift plate. The points to which spring forces exerted by the blade springs are applied are located on a surface of the lift plate opposite to the optical disk.