Abstract: An anodization apparatus for anodizing the surface of a semiconductor substrate by supporting the semiconductor substrate between a pair of electrodes in an electrolytic solution and applying a voltage across the pair of electrodes. The anodization apparatus includes an elastic sealing member for supporting a peripheral portion of the semiconductor substrate such that a surface portion of a semiconductor substrate remains exposed, a support jig which includes a tapered hollow portion for supporting the sealing member, and a device for introducing a fluid of gas or liquid into the tapered hollow portion. When the fluid is introduced, the sealing member is pressed against and brought into hermetic contact with the tapered hollow portion and with the entire peripheral portion of the semiconductor substrate such that the electrolytic solution is separated into electrically isolated parts by coordination between the semiconductor substrate, the sealing member, and the support jig.