This research examines symbolic meanings of architectural style of Japanese ruling era of Korea through analysis of Expo buildings. Expo buidings of Joseon Product Evaluation Expo(1915), Joseon Expo(1929), and Joseon Grand Expo(1940) are chosen as subjects of this research. Expos held in Korea since 1945 were creatures of colonial reign and their objectives are advertising the advancement of Japan. New and latest architectural styles of Western countries were used as a symbol of advancement in non-western countries. Renaissance style and Secession style in Joseon Product Evaluation Expo and Modernism style in Joseon Expo were introduced as architectural styles that symbolize advancement. On the contrary, the traditional architectural style of Joseon Dynasty was distorted as symbol of backwardness. Latest Western Architectural Styles were used elaborately and Intentionally to symbolize advancement and industrialization by Japanese ruling power and companies. Specially, Modernism style operating as 'symbol of advancement' is characteristic of non-western society in attempt to proceed Modernization through Westernization. Also, it can be suggested that architectures in Modernism style are used in ways to symbolize the advancement of the colonial reign authorities within the colonial society.