Smith（1979）年提出租隙（rent gap）企圖解釋仕紳化（gentrification）後，引發了租隙在理論基礎與實證方法上的討論。有關租隙成立之假設命題部份，包含資本移動、反循環投資與中心都市內鄰里所引發之不動產貶值循環等現象，不論在歐美都市或台北都會區之實證測試，均無法完全符合各項命題。 台北都會區之都市空間發展歷程與歐美都市空間發展型態並不相同，且資本並未由都會中心地區抽離，亦未有明顯的仕紳化現象，但相關實證工作已驗證出單一時點租隙的存在。不過因測試地區未普及，加上測試時間偏短，未能有效進行租隙存在意涵的討論。 故本研究以資本投入的觀點，選定台北都會區中適當地區（大安森林公園週邊、吳興街沿線與迪化街沿線各里，分別代表區域性資本投入高、中、低之區域）進行連續性租隙測試，並分析租隙的形成、變動型態及與資本投入之相互關係。此外，台北都會區與台北市內並未產生明顯仕紳化地區，以租隙論述進行都市空間發展歷程的闡述時，是否會產生解釋力不足的問題，亦為研究論述的重要內容。 / Smith proposed rent gap in 1979, which tried to explain gentrification then involved huge discussion of rent gap application in the theoretical basis and practical approach. The hypothetical premises of rent gap to be sustained include capital switching, counter cyclical investment and the depreciation cycle of inner city neighborhoods, etc. However, the practical tests whether in Western Cities or Taipei metropolitan cannot correspond completely to each premise. The urban structure of Taipei metropolitan is not exactly the same as Western Cities; besides, capital doesn’t disinvestment from the center of urban area and there is no apparent gentrification phenomenon. Nevertheless, the related pracitcal work has been examined the existence of rent gap in a single time point. The rent gap existence doesn’t have further discussion due to examination areas doesn’t broad enough plus examination period is short. Therefore, this research adopts capital investment viewpoint, selects the appropriate area in Taipei City （Ti-An Forest Park, Wu-Hsin Street and Di-Hua Street, which represents district capital investment high, medium, and low.）, does the continuous rent gap tests, and analyzes the inter- relationship of formation of rent gap, changing style and capital investment. In addition, Taipei metropolitan and Taipei City don’t have obvious gentrification, once the rent gap theory is adopted to explain urban structure, whether the explaination be powerful and proper is also an important and main content in the study.