Many educators and teacher-librarians have emphasized many times on the necessity and the educational value of the school library. But actually the necessity and the educational value of the school library is not recognized as the most important ones in the educational system. Therefore I tried to find out several ways on the development of the school library and the promotion of the teacher-librarian focusing on recognition of the necessity of school library. In order to develop the school library, it is necessary that the function of the school library should be maximized and transformed to effective system. I would like to suggest the following methods : 1) Transform the present school library into the school library media center. 2) Connect the running system S.L.M.C. to the curriculum of the school. 3) Emphasis of the reading education. 4) Guidance on the use of library. At last I studied on the definition, the legal status and the education of the teacher-librarian.