本文主旨是要說明：就《道德形上學》的論述而言，康德在何種意義上能夠被視為一個契約論思想家。本文將從兩條線索出發來理解康德所提出的契約論，這兩條線索分別是：康德的財產權理論、以及契約論中處理政治權威正當性時所必須面對的統一性問題。 本文認為：康德所提出的作為理念的原初契約，是一種提供給已處身在政治社會之下的個人，去設想當下所面對的法律強制力之正當性的方式。藉由康德在《純粹理性批判》之中對於「理念」的界定，可以將賦予原初契約一個確實的契約作用：人民的同意。儘管是一個被想像的同意，但康德賦予它積極的意義即形塑公民為一個自主、自律的主體，因此，在這個面向上，本文認為康德提出了儘管與霍布斯、洛克、盧梭迥異但卻仍然極富意義的契約論。 / The purpose of this thesis is that Kant should be seen as a theorist of the social contract theory in the discourse of the Metaphysics of Morals. This thesis will perceive the social contract theory provided by Kant in accordance to two clues, including the theory of property and the problem of unity. The main point of the thesis is that the original social contract as an idea of reason is the method providing for the individual existing in the civil society of constructing the legitimacy of the political authority. By definition of “Idea” in Critique of Pure reason, Kant gives the original social contract a meaningful function: the consent of people. Though the consent is a concept imagined by the people, Kant gives it a positive meaning of forming the people to the independent subject in politics. In conclusion, this thesis claims that Kant provided a meaningful social contract theory different from other theorists in the social contract tradition, such as Hobbes, Locke and Rousseau.