To provide a bookmark which can easily and firmly be fixed to a page, and by which the swelling of a book can be suppressed to a minimum even when being pinched between pages in the bookmark which is inserted between pages of a book.

A sheet structure the whole of which is approximately 1 mm is formed by using a resin material. A clip section of a folding-back shape is provided on this bookmark. In this case, the clip section pinches a page when the slip section is simply inserted while being rotated, and can easily and firmly fix the bookmark by the elastic force of the clip section.