本文試圖延伸傳統的雙向投資模型，在產業分工體系下強調中間財投入的重要性，以便將不同類型的國際資本移動現象，整合在簡單的架構內進行討論。在中間財自給自足的情況下，一旦外來衝擊改變了產品的生產技術，水平雙向與垂直雙向投資很可能同步發生；然而當中間財開放貿易後，一國將根據比較利益決定專業化分工與對外投資的型態，所以外在因素只會單獨引發垂直或水平投資。透過理論推導與數值模擬的結果可知，偏好、稟賦與生產補貼等因素能否改變均衡的要素投入比例，以及非貿易財與中間財部門的要素替代彈性，將是左右國際投資類型與方向的關鍵。

The paper investigates the phenomenon of international capital movements within a specific-factor framework and highlights the role of intermediate inputs under the vertical production structure. Depending on whether the intermediate good can be traded or not, the vertical and horizontal cross-hauling may occur simultaneously in response to exogenous shocks. The relevant results based on theoretical analysis and numerical simulations show that the effects of preference, factor endowment and policy changes on the equilibrium input ratios and the factor elasticities of substitution cross sectors will be crucial in determining the direction of international capital movements.