The Central Bank of the Republic of China (Taiwan) Act Article 18-1

The maximum amount of national currency that may be carried or mailed into or out of the territory of the Republic of China(Taiwan)shall be prescribed by the Bank.Currency in excess of the aforesaid maximum cannot be transported into or out of the territory.
中文原文 中央銀行法第18-1條
攜帶或寄送國幣出入境之限額,由本行定之。
攜帶或寄送國幣出入境超過本行依前項規定所定限額者,其超過部分,應予退運。

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