This thesis aims at reviewing the wearing aspect and formation of Chosun ceremonial dresses for meal and finding out the thought reflected by them from the standpoint that dresses themselves should be taken as one of the phenomena in culture. That is men's ceremonial costumes and confucian costumes of the royal family and the gentry family in Chosun is reviewed focused on the formation and the wearing aspect of Po, Which is a kind of them. And in the context of the phase of the times. I also considered the thoughts reflected on the clothes such as confucianism, Ying & Yang Theory, and the symbol and the thoughts of patterns in relation to the clothes. Confucian influence was the main force for the Chosun prohibitions for clothes. The major reasons for the prohibitions for clothes were as follows. First, they reflected confucian Chung myoung chooui(the principle that everything should be where it belongs). That is the prohibitions for clothes were used in the means to maintain feudalistic social order. influenced by social rank system. Second, they reflected confucian ethics in the means to recover social disciplines with the maintenance of traditional customs. This shows well in the restriction of luxurious items in dressing included the prohibitions for clothes. Third, they reflected Chosun's toadysm toward China. With the influx of Chinese style of dressing then government even changed the style of uniforms for public officials into that of Chinese resulting in dual styles of dressing. Ying & Yan Theory greatly affected the colors of Korean clothes and reflected toadysm toward China. too. The theory was embodied by prohibition of such colors for clothes as white, gray, and jade green. I reviewed the twelve patterns on Myunpok, Ten-Longivity patterns and Four-Gracious plants patterns in order to analyze the symbolism and thoughts of patterns for clothes. Nansam, Dopo, and Shimui worn by confucian scholars ensures that those clothes bears confucianism and philosopical factors. As shimui was worn by many people it appears in Chosun scholars' studies and a Chinese book called "Yeki". I reviewed the origin, procession, and ornaments of four ceremonial clothes and tried to find out the confucianism in them. First, In Kwanrei (the coming-of-age ceremony) remained ancestor worship and respect for manners. The clothes for this ceremony granted the rights and responsibilities of and adult to the wearer. The royal Kwanreipok had different dresses for each rank. As Samgapok, the crown prince wore Iksunkwan and Konryongpo for the first ritual, Wonryukwan and Kangsapo for the second, and Myunrukwan and Konpok for the third. The rank of the King's grandson was lower than the crown prince's. This example shows that Chosun people respected manners and thought the basic confucianism "God and people are equal." at the Royal court. Second, as Honreipok(wedding gown), the crown prince wore Myunrukwan and Konpok for Daereipok, Wonyukwan and Kangsapo for Napjing and Tongwoo, and Iksunkwan and Konryongpo for Chekbinui. But common people were allowed to wear an official outfit only for wedding in the means of congratulation on the most important day of their life. Wedding gowns which reflected Ying and Yang Theory emphasized the thought that union of a man and a wife is the most important event in life. Third, Sangrei(funeral) was the last ritual of a human being to send off the deceased. The mourning dresses expressed lamentation of the people left behind. Five-Dress-System for each the relative degree of familarity showed the solemnity and formality, which represented the formality of confucianism and ancestor worship. I reviewed the mourning dresses by dividing them into royal, Yangban's, and commons. They were featured by the fact that there was only one style for every walk of life. It is construed that anyone in mourning can wear the same clothes since he feels the same way regardless of his social rank. Fourth, Chereipok(sacrificial rite dresses) had different styles for each social rank. The King wore Myunpok(Kuryumyun and Kujangpok) were recorded to be worn first in the fourth year of King Taecho's ruling. The crown prince wore Palryumyun and Chiljangpok for sacrificial rite dress which was finally settled when King Sejong was in power. Common people wore Dopo, Shimui for the rite dress in the beginning of the Chosun Era and wore Dopo after Japanese invasion of Korea in 1592. In conclusion, confucianism played the main role in ceremonial dress system of Chosun and that was because it emphasized the ethics of action in life, which was different from other religions. It is true that cause-oriented thoughts and Chung myoung chooui in confucianism drove all ceremonies to extreme manners, discriminating the people who belonged to the lower social rank, and resulting in extremly luxurious life style. However, they also created a unique trend and clothes culture in the Chosun Era. I wish that this thesis provieds important information and direction for furthur studies in the future.