This research is to reveal an aspect of costume culture interchange in the relationship of the early Chosun Dynasty, by considering the imported goods from Japan, of the trading goods derived by the trade diplomacy between the two countries in the early Korea-Japan relationship in the medieval era. The research results are as follows. A good-neighbor Policy in the early Chosun Dynasty was established by a link of a barbarian ban policy to blockade the frequent intrusion by Japanese barbarians. The exchange was the form of presenting a return present in return for a tribute to the Chosun Dynasty from the Japanese envoy, which has a polycentric characteristic. Pusanpo, Naipo, and Yumpo were designated as the open ports, which played a pivotal role in the Korea-Japan exchange. In trading goods between Korean and Japan. the imported goods from Japan to Korea were a wide variety of items primarily such as dyes, mordant, medicines, steel, spicers, etc. In particular, Somok used as a red mordant, which were intermediate goods to Southeast Asia, was the most heavily-traded items of imported goods from Japan. It had been consumed primarily as a raw material making the costume suit of the royal family and the aristocracy. The increased import of Somok was derived from a thought of preferred red color by our people. As its inflow was increased. the costumes tended to be luxurious In early Chosun Dynasty and resulted in social issues. This active trading from the early Chosun Dynasty caused from the communication of the Japanese envoy. In addition the study of the trading provided an opportunity that can glance at an aspect of the costume culture, though It was fractionary.