| CPC C25D 11/20 (2013.01) [C25D 11/12 (2013.01); H01B 13/0036 (2013.01); H01L 21/486 (2013.01)] | 16 Claims |

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1. An anodizing method comprising:
subjecting a surface of a valve metal plate to a plurality of times of anodization; and
forming an anodized film having micropores present in a thickness direction of the valve metal plate and having a barrier layer present in a bottom part of the micropores, on the surface of the valve metal plate,
wherein in steps of second and subsequent times of anodization of the plurality of times of anodization, a current increasing period and a current keeping period are continuous,
the current increasing period is a period in which a quantity of current increase is more than 0 amperes per square meter per second and 0.2 amperes per square meter per second or less, and which is 10 minutes or less,
a current is kept at a constant value during the current keeping period, and the constant value is equal to or less than a maximum current value during the current increasing period, and
a counter electrode is arranged to face the valve metal plate, and a conductive load member is electrically connected in parallel with the valve metal plate.
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