This paper examines the relationship between Criminal Law, postcoloniality, and women’s sexuality in postwar Korea by exploring the genealogy of the “woman free from habitual debauchery.” This category was specified in two provisions of the Criminal Law, the “crime of mediating debauchery” (Clause 242) and the “crime of obtaining sex under false promises of marriage” (Clause 304). The idea of the “woman free from habitual debauchery” first appeared in relation to the “crime of suggesting debauchery” in the Old Criminal Law of the colonial period (Clause 182), and it was succeeded by the Criminal Law of the newly born Republic of Korea. In this regard, the idea of the “woman free from habitual debauchery” is a useful clue to reveal the coloniality of both the Criminal Law and the Korean society that produced such a law. However, the Criminal Law did not provide the definition of “woman free from habitual debauchery.” This study explores who was actually referred to as such category by investigating precedents. On the trials concerning the “crime of mediating debauchery,” the accusers’ “habitual debauchery” was hardly contested. It was because this category was related to the “minority”—another category of the same provision—and overwhelmed by it, so the accusers were labeled as “obviously vulnerable victims.” On the contrary, in the case of the “crime of obtaining sex under false promises of marriage,” “habitual debauchery” was much more controversial. There was no consensus among lawyers about how to define “debauchery” and “habit,” so the accusers’ sexual histories, rather than the defendants’ fraud, were often debated. The so-called “Park In-Soo Affair” was such a case. Therefore, the trials regarding the “crime of obtaining sex under false promises of marriage” functioned as the “public sphere” to verify a sense of chastity of Korean women, to establish a new standard of it, and to socially punish the women who fell short of such a standard. In conclusion, the category of the “woman free from habitual debauchery” was not a nominal trace that legal scholars carelessly forgot to delete, but was a means of disciplining women’s sexuality and rebuilding male-oriented gender order that had been destroyed by the war.