Abstract
Hong Tae-Yong was both a philosopher and scientist in 18th century Korea. The fact that he proposed the roating earth theory is well known, but the appreciate for it has not been established. In this paper, firstly the previous investigations are surveyed and indicated a problem in there. In the many cases the originality is discussed in the connection with Copernican theory without the examination of Hon's own writing "Uisan mundap" mentioned the roating earth theory. Thus, secondly examinating "Uisan mundap" the characteristics of his roating earth theory and why Hong could propose his theory are considered. Hong's roating earth theory is a moment of the development into the infinite universe theory and a part of his cosmology. There his relativism and the mechanical viewpoint to nature played the important roles
