ically illustrating a stamper held in a fixed-side metal mold for injection molding by means of the eccentric retainer shown in FIGS. 4A and 4B; andFIG. 7 is a plan view showing an embodiment of disk according to the present invention.DETAILED DESCRIPTION OF EMBODIMENTSDisclosed below are an optical-disk production apparatus and an optical disk as embodiments of disk production apparatus and disk,