We analyze the effects of the inflow of foreign workers. We did economic and
social analyses about this issue. At first, we pointed out social issues caused by foreign workers. Second, we analyze the inflow of foreign workers from macroeconomic and microeconomic perspectives. Macroeconomic analysis is organized by using the theory of foreign workers’ surplus. Microeconomic analysis especially focuses on the effects on native workers by being based on “Dual Labor Market Hypothesis”. As a conclusion, we suggest the policies dealing with this issue, making good use of our analyses.