This paper is about liaison of the natural fears about the classics of the literature of Japan at the time, the people`s concept of sex between men and women are how. Take a look at the reflected. As you can see the relationship between the men and women in the dictionary definition of adultery `inappropriate love`, or refers to the `an inappropriate relationship`. Love affair is contrary to morality take a backseat. Japan`s sexual morality is a lot you don`t understand when you see the part of us. That`s a Japanese citizen, not everyone does that mean you. The ancient Japanese people are taken the Meiji Restoration of the practice of polygamy (明治維新) by modern system since changed. And adultery. The adultery in Japan had disappeared in the late 1940s. Modern physical relationship, or the concepts of the affair, in return for sexual intercourse of men and women. Once upon a time and the modern concept of sex. In ancient literature, especially ＂Manyoshu＂ in extramarital affair at this point is the song of many song that can say. Japan is in love songs of men and women so. At that time, having an affair not power, and in women, and an ordinary of men and women of noble rank as the central love. But ＂Manyoshu＂ the songs of Azuma(東歌) and Sakimoori(防人歌), in having an affair can not find out. Of course, a love affair is not appear, but I`m sure you. In addition to the songs looking in the final announcement on the songs of＂ Manyoshu＂. Next time I`ll introduce another paper about the prince Siki`s songs, Abenoiracheume`s songs and Nakatoomminoasomiazumahito`s songs.