「共居」指多個房客們分攤居住空間，透過共享公共區域以建立互動與情誼的居住形式。「玖樓共生公寓」(玖樓)是台灣第一個將共居作為商業模式的企業，創立於2015年，透過向房東租用老舊空屋重新裝潢、擴大共享空間設計，及舉辦活動增加房客們交流機會，以因應租賃市場失衡與國人歸屬感失缺之問題。但近年來玖樓房客們主動交流的意願逐漸下降，恐失去共居的核心理念—建立人際連結。究竟應如何促進房客交流？如何有效提升房客歸屬感？本研究採「行動研究法」探討玖樓經營難題，研究者至荷蘭與英國參訪9家共居標竿企業，並歸納其經營特色。本研究結果可供玖樓與我國其他共居企業營運面的改善參照，亦期待藉共居的推廣，降低孤獨感而引發的負面影響。

Co-living, or co-housing, refers to a form of housing that tenants sharing community spaces and facilities to enhance the interaction between them. In 2015, in response to the imbalance in the rental market and the lack of belongingness to the Chinese people, “9floor”, Taiwan’s first co-living company, was established to improve the above problems. They rent a room or space from the landlord, be allowed to make it more modernization, then rent it to the tenants. The concept is like a sub-lessor but gives tenants more than that because of two things. First, co-living increase the proportion of shared space, such as open kitchen, comfortable living room, etc., allow tenants to know each other when they’re in the space. Second, the company organizes activities to actively and passively increase the opportunities for tenants to understand each other deeply. But by the end of 2018, the willingness of tenants to participate in activities in 9floor gradually declined, and the benefits of co-living and connection could not be realized. How does co-living allow tenants to choose to communicate with others? What are the ways to build or enhance the belongingness of tenants? It will be discussed in this study. The researchers used the Action Research to explore the dilemma of the operation of 9floor, went to the Netherlands and the United Kingdom to obtain and summarize the operating characteristics of the benchmarking enterprises. This study is expected to provide research starting points for academics and those who want to know how co-living make tenants live better. This study aims to give a way to balance the rental market in Taiwan, promote the concept of co-living and scale up the market to enhance the belongingness, and reduce the possibility of mental health crisis or crime caused by loneliness.