The purpose of this study is to improve the acoustic environment in libraries and to construct the model of the desirable acoustic environment in libraries, based on the theory of soundscape and soundscape design. In order to think of soundscape in libraries, the author set up the following 3 levels: (1) public space, (2) cultural information centers, and (3) libraries, and examined some examples of soundscape design and the possibility of applying them to each levels. First of all, it is important to clarify the existing acoustic environment of the facilities. Therefore the author investigated the existing acoustic environment of the libraries and the acoustic environmental awareness of librarians by questionnaire, focussing on the public libraries in Saitama and Yamanashi prefectures. The results of this survey are discussed from 3 aspects : (1) sound from the outside of the libraries and undesired sound, (2) sound from the inside of the libraries and undesired sound, and (3) environmental music in the libraries.