To make it possible to prevent a book from naturally closing and to easily flip pages when opening the book.

An instrument for preventing the book from closing during reading the book has a holding plate 1 and a holding plate 3 held so as to overcome the force of a pushing up plate 5 pushed up by a spring 6, the book 8 is sandwiched between the holding plate 3 and the pushing up plate 5, and the instruments are arranged in both side. Thus, there is no need to put the arms or unstable matter, and pages can be changed by lightly pushing down from above the book 8 to draw out and interposing while pushing down to the opposite pushing portion. The instrument can respond to the change of the thickness and position of the book because the holding plate 1 and the holding plate 3 are movable.