Anodizing apparatus

An anodizing apparatus for causing an anodizing reaction on substrates immersed in an electrolyte solution, comprising:

• a storage tank storing the electrolyte solution;
• a substrate holder mounted in the storage tank, and including a first support unit having a plurality of first support elements arranged in a direction of arrangement of the substrates for contacting and supporting, in a liquid-tight condition, portions of surfaces of the substrates, and a second support unit attachable to and detachable from the first support unit and having a plurality of second support elements arranged in the direction of arrangement of the substrates for contacting, in a liquid-tight condition, remaining portions of the surfaces of the substrates other than the portions supported by the first support elements;
• and
• wherein the second support unit includes a first portion second support unit having support elements for supporting first portions of the remaining portions of the surfaces of the substrates, and a second portion second support unit having support elements for supporting second portions of the remaining portions of the surfaces of the substrates.