Customs Act Article 39
The foreign currency prices for imported goods liable to ad valorem duty shall be conversed into New Taiwan Dollar, and the exchange rate used for the conversion shall be published regularly by Customs Administration in reference to the spot rate of the foreign exchange market.
中文原文 關稅法第39條
從價課徵關稅之進口貨物，其外幣價格應折算為新臺幣；外幣折算之匯率，由財政部關務署參考外匯市場即期匯率，定期公告之。