Abstract
According to the Ministry of Education, Culture, Sports, Science and Technology, in 2015 the number of public libraries providing e-book to users is 16% in Japan. It is only 54 municipal libraries. In public libraries, the spread of e-books is sluggish. Even in the Yokohama campus library of Tokyo City University, there are still 200 e-books and it cannot be said that they are popular. Therefore, using the Yokohama Campus Library as a case, we analyze the factors of the gap between e-books and the library's business model using DEMO.