1980年以來，台灣開始對外投資，結果一方面造成生產的外移，一方面也使得國內製造業結構迅速轉型，從而勞動結構也受到明顯影響。本文先將勞動變動拆解成產業內變動與產業間變動，結果我們發現台灣勞動變化先是以減少產業內、非技術勞動為主；然後，在1987年之後，再擴大為產業間的減少。為進一步追究對外投資對國內勞動結構的影響，我們把對外投資區分成赴海外投資與赴大陸投資，並估計其對就業結構的影響。我們利用1980到2002的年資料，並把製造業分成12個產業，進行迴歸分析，結果發現赴海外投資造成對國內技術員工需求的增加，赴大陸投資則造成對國內非技術員工需求的減少。由於兩者都使非技術員工的相對比例減少，同時使技術員工相對比例增加，造成勞動結構往上調整的結果，與利用產業內及產業間勞動變動的發現一致。 When Taiwanese firms started their foreign investment in 1980, the manufacturing sector of Taiwan was facing drastic structural changes and, at the same time, the employment structure was also facing significant changes. In this study, we divide the employment changes into "employment change within industry" and "employment change between industry", and we find that before 1987 the decreasing labor demand was caused mainly from "within industry" changes and mainly for unskilled labor jobs. After 1987, there was a greater decrease of labor due to change "between industry" and for unskilled labor jobs, since lots of Taiwanese firms started to invest in Mainland China. In order to estimate the impact of investment abroad on labor demand in Taiwan, we separate the foreign investment into investment in Mainland China and investment overseas (excluding Mainland China) first, and we apply a data set with a annual data from 1980 to 2002 with 12 industries in the manufacturing sector in Taiwan. Applying a SUR method to estimate the impact of foreign investment on labor demand in Taiwan, we find that investment overseas increase labor demand for skilled labor; however investment in Mainland China decrease labor demand for unskilled labor. Since both types of investment cause labor demand to shift to skilled labor, the result is consistent with our findings for the change of labor demand "between industry" and "within industry".