本文以一雙占模型探討一國之最適貿易政策。在模型中國際間敵對廠商之間存在 「委託代工」 (OEM) 契約。 我們研究在此情況下委託代工貿易型態的經濟理性與最適貿易 政策。在 OEM 市場為買者訂價的假設下，我們證明 OEM 貿易型態的發生與否不僅取決於貿 易政策變數與貿易國家之比較利益， 並且必須考慮敵對廠商間之策略性互動。 我們發現就 OEM 受委託國而言， 對其 OEM 產品之出口應予課稅，但對出口至第三國之產品則應予補貼 。

　　　　　We examine the optimal trade policy in a duopoly model where international rival firms compete in a final goods market. The domestic firm signs an OEM (Original Equipment Manufacturing) contract with and produces the final goods for the foreign firm. When the price in the OEM market is decided by the foreign firm, we prove that whether a trade pattern with the OEM contract exists depends on the comparative advantage of trading countries and on the strategic interaction between firms. We show that the domestic country should tax its exports of the OEM products, but subsidize the other exports of final goods.