PURPOSE: A disk driving device is provided to stably support a disk mounted on a chuck base. CONSTITUTION: A chuck(110) includes a plurality of elastic pieces(113). A central hole of a disk(1) is inserted into an external surface of a chuck base(111). The elastic pieces are formed on the external surface of the chuck base. The elastic pieces support the disk. Upper left and right widths of the elastic pieces are narrow. Lower left and right widths of the elastic pieces are wide.
