To enable a user of a book shelf to open a book taken out from the book shelf without holding by both hands at the spot, to inspect something, and to make a note.

In this book shelf 1, a number of hanging holes 3 are arranged at vertical intervals on the inside of a shelf board 2. Shelf receivers are hung on hanging holes 3 at positions of desired height to receive shelf boards 4, 5 so as to enable shelf boards 4, 4 to be detachably attached on positions of desired height. The shelf board 4 with laying board 6 is equipped with a shelf board main body 7 with inward directed L-shape guide parts 7a in downward protruding conditions on both side edge parts. Lower face sides of side frames 6a formed on both side parts of the laying board 6 are supported by the guide parts 7a and side faces of side frames 6a are made supported by the guide parts 7a.