To provide a book setter for setting the turned page, to be manipulated with one hand even for a thick book.

A half-circular arch, having a thin space at the inner side of the surface, is formed in the respective center part of a rectangular fixing plate 1 and a pressing board 2, respectively so that a center shaft having weights at both right and left side can be interposed vertically and a spring board 4 is assembled via a space in the center. The pressing board 2 accommodates a thin space therein, and has an arm adjusting window 9 on the upper surface so as to insert an arm 6 into the space. A heavy fixing bar 7 having an anti-slipping tape 8 wound around thereon is attached to the tip of the arm. An arm adjusting knob is attached on the rear end upper surface of the arm inserted in the pressing board via the arm adjusting window 9.