This paper proposes to delineate the idea Lee Hyo-sok is supposed to have entertained about the essence and function of sex in close reference to his view of man and nature. To him sex is more than anything else something liberating, anti-intellectual and taboo- busting, and sexual desire has affinity with nature insofar as it draws upon animal instinct. Sex, therefore, is essentially healthy and creative. Even voyeurism, a form of sexual perversity, is regarded by him as a harmless process of initiation into knowledge and growth. We should not forget, however, that in Lee Hyo-sok``s work sex is not always hailed as something salutary or redeeming, and the negative aspect of sex can be excruciatingly verified when we examine various cases of married life or sexual relation between man and woman in general. In some instances sex simply leads a married couple to a catastrophe and in others sex proves totally helpless in sustaining marital or extramarital relations. To Lee Hyo-sok sex in its primeval form is healthy and redeeming, but in real life sex is found more often than not to be negative and degrading, or at best it is powerless. Hence the ambivalence of his attitude toward sex.