The purpose of this study is to find out changing process of 'Kyungsung Libraries' in the Japanese colonial era by comparing and analyzing through the books and Journals of Korea and Japan. The subject scopes of this study are as follows ; 1) 'Kyungsung Libraries' in Japan Chamber of Commerce and Industry founded by Japanese named, 'San Gu Jung(Yamaguchi Sei)' 2) 'Kyungsung Libraries' founded by 'Yoon Ik Sun' in 'Chiwoonjung' 3) 'Kyungsung Libraries' founded by 'Lee Bum Sung' beside 'Jongno Tapgol Park'. This study studies each three libraries and simultaneously, relationship between mutual relation of these three libraries and other libraries. As a results, the books of San Gu Jung(Yamaguchi Sei)'s library were inherited to those of other two libraries. Also, Despite of eagerly practicing public service of the age, however, independent development of each of two library founded by Koreans was very limited under the influence of Japanese colonial.