本研究目的在於解讀臺灣「閒置空間」個案，包含荒廢閒置、投資決策錯誤、重覆再利用現象的決策背景。並應用代理人、尋租理論及政治地理學理論，提出閒置空間成因的理論解釋。應用多元對應分析方法，取材1977～2014年，內政部公共工程委員會公布暨相關報導閒置空間案件共515件。研究發現透過工程發包給私人營造利益集團，建構了「土建利益複合體」。造成閒置空間的主因是：基礎設施項目不符地方實際需求。金額規模越大項目，越缺乏市場性評估，且與人口規模、密度、財政壓力無絕對關係；閒置空間項目，大多使用現金給付，並投資在公有土地及建物的再利用，且有效率的達成剪綵政治需求。政治代理人基於選票的考量與壓力影響下，導致基礎設施閒置、荒廢，符合選票尋租與政治地理學論述。建議落實基礎設施決策前的市場性評估制度，減少選舉政治干預，增加民眾參與監督，將可以減少閒置空間。

This study seeks to provide insights of Taiwan's Idle Spaces, which involves investment failure and the ＂reuse policy＂ issues. To further elaborate on the causes of Idle Spaces, this study also provides theoretical interpretation of principal-agent theory and rent-seeking and political geography theory. By means of Multiple Correspondence Analysis, the data analyzed were the Public Construction Commission announced a total of 515 cases, between 1977 and 2014, related to Idle Spaces in Taiwan. The study found that the relationship between the project and the construction interest group would create ＂the Civil Engineering Construction Industrial Complex.＂ The causes of Idle Space were: Infrastructure projects were failure to meet the local actual needs that led to Idle Spaces. The larger scale the project, the fewer done the market assessment, which without any association with demography, population density, and financial pressure. To meet the political policies, most projects of Idle Spaces are focused on, the cash flow investment, to public-owned land, and building reuse. Since political agents are mostly affected by campaign pressure, it often leads to the incompletion of infrastructure projects, which corresponds to the discourse of ballot-seeking and political geography theory. However, many are concerned that even though infrastructure investment promotes economic development and social welfare prosperity, it also leads to government financial deficits. Ultimately, a better market assessment system, fewer political intervention, and encouraging local participation as an inspection would reduce the number of Idle Spaces in Taiwan.