The purpose of this study is to analyze the configuration and characteristics of public library spaces in conjunction with the societal changes in South Korea. To achieve this, a visible analysis was conducted to compare the spatial configuration and functional area ratios of the main reading floors of centrally managed public libraries with an area of over 2,500㎡ to less than 9,000㎡ established in Seoul metropolitan area since the 2000s.Through this research, it is evident that the configuration and characteristics of public library spaceschange according to social and environmental shifts. Therefore, in future public library space plans should consider not only the size of the space but also the social environment, such as social and policy changes.