This paper has focused on comprehending the interior designs and characteristics of modern department stores in Korea by looking into the birth and changes of those built under the Japanese Forced Occupation Period. The first modem department stores including Mitsukoshi, Georgia and Hwashin Department Stores began to appear in Korea under the Japanese Colonial Rule. They considered a variety of architectural elements like construction planning, shop arrangement, path of customer movement and interior design. The interior of modem department stores aimed to pursue the so-called modernization movement, but failed to fully contain the unique characteristics of the times in that particular period. Modem department stores took on new western styles prevailed in Korea and were characterized by the eclecticism in which various architectural forms exist together. In other words, their interiors implied a sign of the times in the confusing and corrupt world then. Especially those modern department stores were designed, repaired and extended by foreign designers who were ignorant of the history of Korean architecture. What is worse, their further remodelling practices made big mistakes by considering only functional and economical aspects and giving a back seat to the architectural and historical value of existing modern department stores. Therefore, we should make more efforts to study and conserve the fundamentals of modem architectures like modem department stores in order to have better understanding of the aesthetic value of indoor space and facilitating smooth communication between past and present.