Industrial Group Act Article 10

As for industry with more than two trades, Ministry of the Interior and Ministry of Economic Affairs jointly determine which industrial trade association it should join, those conforming to Article 7 after joining an industrial trade association should also join another industrial trade association at the same time.Those out of special zones have to get approval of both Ministry of the Interior and Ministry of Economic Affairs to join the industrial trade association in the near special zones.
中文原文 工業團體法第10條
兩業以上之工業,得由內政部會商經濟部命其合組工業同業公會。
合組後如合於第七條之規定者,並得命其分組工業同業公會。
不在特定地區內之工廠,得聲請內政部會商經濟部同意後,准其加入鄰近特定地區內同業之工業同業公會。

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