To provide a book cover which is easy to attach to and detach from a book, does not move or slip off during handling the book, and is capable of hiding the title of the book from others when the need arises.

A non-transparent base sheet 6a is formed in a size approximately equal to a size of integrating a front cover 13, a spine cover 12, and a back cover 14 of a book which is an object to protect. An adhesive layer 7a having weak cohesion capable of releasing is formed over the whole back side of the base sheet which touches the book. The book cover is attached to the covers of the book by the adhesive layer.