To provide a book cover having a function capable of having no possibility of closing freely a book and capable of reading the book as it is, in addition to the function conventional books have.

The book cover is characterized in that a belt, which is positioned on the front of the book cover and is employed for fixing the book so as not to be opened as it is closed, is fixed on the opposite side of the original case, in that a transparent belt 5 having a function which does not close the book cover, built in the book cover is drawn inside and drawn horizontally so as to press a page to be opened, and in that the transparent belt is used to be hooked on a hook 6 or the like.