地方自治有三要素：居民、自治區域、自治權。本文擬就縣市合併所引發之自治區域變革做一探討；闡述在精省後，縣與直轄市都是地方自治層級中第一層級（鄉鎮市為第二層級），「縣」與縣同級之「市」（過去省轄市）為何期待升格為直轄市？為何要合併升格？為何要以公投方式進行？合併升格的過程如何落實「住民自治」？ 縣市基於人事權及財政權擴張而期待升格為直轄市，再加入都會社區發展（廣域行政）之共同生活圈之考量乃有縣市與直轄市合併升格之倡議。合併升格有其利，亦有其弊，但在現行法制及政治局勢下，縣市與直轄市並不易合併升格，乃有透過公民透票方式達成之論述。惟回到問題根源，合併升格是不是必然的選項，是不是有其他的機制作為。而在設計地方自治之機制時，應在尊重地方之特殊性的基礎上，以宏觀的國土重劃思維，並以「城市型的地方自治」與「鄉村型的地方自治」概念來調整自治區域。

There are three components to facilitate communalism, which are residents, autonomous regions, and the power of autonomy. This author seeks to discuss the changes in an autonomous region. After the downsizing of the Taiwan Province, the counties and metropolitan cities become equal as the first same level of communalism, while the hsians, townships and cities are the second level of communalism. Why do the counties, along with the cities (the provincial cities before) equivalent in their level to the counties, wish to be promoted as metropolitan cities? Why does this have to be done by referendum? And, how do they consolidate the principle of “resident autonomy” in the process of “mergence and promotion”? Since the counties and cities seek to expand their powers in personnel and finance after their promotion to metropolitan cities, and they prefer to organize their “common living circle” after metropolitan community development (wide-ranged administration), they tend to pursue their mergence and promotion. There are also benefits and demerits in this process. It is not easy for counties and cities to merge with metropolitan cities under the current legal institution and political atmosphere. As a result, they tend to fulfill their wish to merging by referendum. Hence when we trace back to where the problems are, it is apparent that mergence and promotion is not the only option for how their wish comes true. We also explore other possible mechanisms in this study.