This study is about the similarities and the individualties of the traditional costumes in the ruling classes of Koguryo(高句麗), Bakjae(百濟), and Shilla(新羅). The analysis is based on the views of historical reformation on$\boxDr$Sam-gooksagi(三國史記)$\boxUl$Bongi(本紀). The costumes that were worn by the governing classes are categorized by the following, official duties, wars, ceremonies, and recreations(hunting). Up to the present time, there has been a great tendency to emphasize the similarities of the Three Kingdoms' costumes among most of academic researchers. However, the conceptions of individualities of the costumes among the Three Kingdoms were conceived by the facts that geological environments, political systems, social traditions, social aspects, and foreign affairs. The Three Kingdoms had different official rank systems along with official costume systems. Monopolization of official positions of the ruling parties tried to show their dignity and authority through styles of their costumes. The costumes of Koguryo were greatly differentiated by geographical regions ; One direct example is cheak of Pyoungyang and Anak regiona was named as official hats of rulling parties of Kokuryo. However, in this study, the cheak was viewed as a product of influences of Chinese costume. Further-more, the laguan was named as mooguan. Costumes of ceremonial occasions were heavily decorated to symbolize dignity and auth-ority. Metal ornament of headgear and belt, metal shoes were con-sidered as ceremonial costumes. the tight hunting costumes of Koguryo shown in mural pain-ting costumes of Koguryo shown in mural pain-tings were presumed to be spring and autumn clothing. Excavated from Neungasnlee, the hunting costumes inscribed in the gold incense burnner were confirmed as hunting costumes of Bakjae. The individuality of the costumes of the Three Kingdoms could also be supported by the fact that they had different climates. The temperature difference between Gipan region and Kyoungjoo(慶州) region was emphasized. Especially winter clothing would have had a big difference in style than the summer clothing. Through the research summarized above, this study was able to confirm that each of the Three Kingdoms had developed individualized costumes based on their geographical, cultural and environmental factors. Furthermore, through this study, it was possible to find out the difference as well as the similarities of their costumes according to each of their people's sociopolitical status, awareness of indepen-dence, andunique historical and traditional charactoristics.