This study considers that the establishment of a public library within multi-use complex is one of the most effective ways to expand infrastructure of public libraries in Korea. A survey on the complexation rates of public libraries in Seoul was made through on-the-spot visits and telephone interviews. It turned out that out of all 112 public libraries in Seoul, 55 of them are in multi complex buildings. In order to efficiently establish public libraries to multi-use complex, absolute consideration on the size, location, and space should be made. Moreover, if necessary, additional complexation with commercial facilities, schools, and local government buildings should be made.