To enable a booklet cover to be attached to a book and a notebook in a usable state of a bookmark without considering the longitudinal direction of the book and the notebook.

In the booklet cover (for example, a book jacket 10) which has a book protection part 60 along the back of a booklet (for example, the book 20), at the back protection part 60, one ends of the bookmarks 40, 41 are fixed to the central part of the back protection part 60 on the side coming into contact with the booklet (for example, the book 20) or the vicinity of the central part of the back protection part 60. Alternatively, the bookmarks 40, 41 are each in a string state at least at one end, and, when the distance in the longitudinal direction of the back protection part 60 is set to "1", the bookmarks exceed "0.5".