To prevent a page from becoming jammed by a booklet medium deformed by the curved part of a transport passage.

A page turning roller Rr1 incorporates a one-way rotating clutch to be driven to rotate in an arrow (d) direction only when the roller Rr1 comes into contact with the pages to be spread of a booklet medium P to be transported toward a page turning device A1 from a curved part W. When the booklet medium P is transported from the curved part W, the turning roller Rr1 is always kept in contact under pressure with the booklet medium P. Consequently, the booklet medium P deformed by the curved part W is transported while being straightened by the roller Rr1. Thus the end part of the deformed booklet medium P is smoothly transported without colliding with the movable guide G3 of a page turning part.