Certified Public Bookkeepers Act Article 21

A municipality, county, or city association of certified public bookkeepers shall be organized by at least thirty (30) certified public bookkeepers practicing in that particular administrative region; if the total number of certified public bookkeepers practicing in the same administrative region is less than thirty (30) persons, they shall join the certified public bookkeepers association existing in an adjacent administrative region, or organize a general association jointly with the certified public bookkeepers of such adjacent administrative region.
中文原文 記帳士法第21條
直轄市及縣(市)記帳士公會,應由該行政區域內開業記帳士三十人以上發起組織之;其不滿三十人者,應加入鄰近區域之記帳士公會或聯合組織之。

English translation for reference only; the Chinese text prevails. Not legal advice.