To provide a compact pocket for a page to cover an upper end corner of the page by retaining the corner to enjoy comfortable reading without discretely turning over the pages even by a wrong attitude of reading a book or a wrong circumferential environment.

The pocket for a page diagonally covers an upper end corner of a book or the like. In this case, the book has side faces 3 formed at folding lines for compressing at both sides of a cover surface 1 to be adhesively fixed by an adhesive pin 5 to the cover surface of the book or the like and a retaining surface 4a of an elastic protrusion folded in a two-page spread from about a center of a page surface 2 of the side covering the page.