Labor Union Act Article 9

The number of corporate union of the same scope organized in accordance with Subparagraph 1 of Paragraph 1 to Article 6 of the Act shall be no more than one.The number of professional union of the identical type organized in the same municipal city or county (city) shall be no more than one.
中文原文 工會法第9條
依本法第六條第一項所組織之各企業工會,以組織一個為限。
同一直轄市或縣(市)內之同種類職業工會,以組織一個為限。

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