To provide a binding material for forming a cover, the range of choice in the pattern of which is made wider.

This binding material has a paper portion 11, by which a front cover is formed, and a paper portion 13, by which a rear cover is formed. At least either one paper portion of these portions is made longer than the width of a book. In the paper portion 13, a first folding crease (a) is formed at a position, the width of which is equal to the width of the book. At the same time, a second folding crease b is formed inside the first folding crease (a). Under the state that the paper portion 13 is folded back at the second folding crease (b), the binding material is put in a side stitch book binding machine so as to put the binding material and a text into an integral body. Under the state that the rear cover is open, the extending portion can be widened at the folding crease (b), a larger pattern can be designed by utilizing the wide spread.