台灣的先住民族有平埔族及高山族二大族群，西拉雅族為平埔族群之一。荷蘭據臺以前，臺灣島上全屬番地，而分布於臺灣西南部的西拉雅族，以狩獵、漁撈及游耕為其主要之經濟活動，對於土地並無所有權的觀念，土地是共有的，頗為類似「封閉的共用資源」，已略具排他性質。在清治以後，由於漢移民不斷湧入，荒埔地逐漸減少，為提高番地之生產效能及維持社番基本生計，西拉雅族傳統之經濟活動，當須配合改變，然而，生產型態及技術之改變，不僅形成水田稻作農業，亦導致番社土地由共有型態轉變為地權私有化。清廷為保護社番之地權，禁止漢人私墾荒埔地，鼓勵社番自行墾耕番地，如社番不自墾，准許番社或社番將番地租與〈給墾或佃批〉漢人，漢人以「代番輸餉」方式合法取得番地管耕權，而番社仍保有大租權。爾後並形成在同一番地上存有大租權與小租權，而且可以各自分別處分其權利，在多層地權制下，番業主僅剩收租權。因社番在經濟上屬於弱勢者，如以番租做擔保，向漢銀主典押或借貸，當期限期滿時，社番常無法清償，番租則繼續歸漢銀主收租，形成社番「地權虛有化」。質言之，本文係從制度變遷及契約理論，配合西拉雅族番契，探討西拉雅族番社地權從傳統共有地權、私有地權形成至虛有地權之變遷過程。

In Taiwan aborigines have Pingpu people and Mountain people. Siraya is one of Pingpu people. Before Dutch occupying, all Taiwan was aborigines' land, Siraya population spread in the southwestern of Taiwan. Hunting, fishing and farming were Siraya's livelihood mostly, there was no concept of ownership, land was used in common. As the land area was used only by village man, it was similar to "the closed-access common resources" which had the feature of exclusive communal property. After Ching Dynasty, owing to Han Chinese had moved into the southwestern Taiwan, wild plains decreased gradually. To improve the productivity efficiency of tribal land and sustain basic needs of living, Siraya people must change their traditional livelihood. As rapid growth of Han Chinese and Siraya people, and the diffusion of technology for paddy rice farming, the tribal land rights had transited from common property into private ownership. In order to protect tribal land rights and encourage village aborigines to plant their land, Ching Government prohibited Han Chinese from developing wild plains illegally. However, if aborigines did not need to develop the tribal land, Ching Government permitted Han Chinese to rent tribal land. Han Chinese obtained usufruct rights and management rights of tribal land by paying the tribal tax, the tribe only kept residual large-rent rights. Therefore, the tribal land rights were divided into split ownership which was called large-rent and small-rent rights. Any owner of those rights could either manage them by themselves or sold them out. In the system of multi-tiered land rights, village aborigines had left nothing but right for collecting rent. Because village aborigines were very poor, they had to borrow some money from Han lender and mortgage their rent to lender. Village aborigines could not amortize the debt usually, if the appointed pay off date reached. As a result, the right of collecting rent belonged to Han lender continually. Formally village aborigines had the large-rent rights, but they were deprived gradually, the large-rent rights turned out empty. In short, the purpose of this paper is to explore institutional change of Siraya's land rights by institutional change theory, contract theory. Through deliberation of Siraya private documents, we can conclude the property rights of village aborigines were transited from communal right into private ownership and turned out to be emptiness or only face right.