To offer an attachable and detachable bookmarker that can be used on books with their back covers paste-bounded on the back face and can easily insert from the upper end of the back cover side without damaging the upper section of the pages even when the books are closed.

The bookmarker has a book attachment 10 that is inserted to a book from the upper end of the back cover side and the necessary numbers of bookmarkers 20 attached to the book attachment and to be used to mark the page. The book attachment is of a round steel wire formed in a reverse-U shape 10a with a certain width and has, on one tip end, a space insertion section 10b of steel wire curved on the same plane but on the outside of the alignment to the reverse-U shape so that it can be inserted between the pages without damaging the upper section of the pages of a closed book and has, on the other tip end, a back face holding section 10c fixed in the direction perpendicularly intersecting with the plane of the reverse-U shape so that it fits to the back cover of the book. The bookmarker has a ring-like holding section 22 to which the steel wire of the book attachment is inserted, bookmarker strings 24 to be placed between the desired pages of the book and a memo paper 26.