To reduce the incidence of a failure to turn a page due to the non-uniformity of rigidity of page paper.

The page turning mechanism for turning the pages of a booklet conveyed through a conveyance path 4, comprises a page turning roller 15 for coming into contact with the surface of the page paper and turning the page while rotating, centering around a rotary shaft 21, detection means 17 and 18 for detecting the position of the turned page, sliding mechanisms 20 and 24 for moving the page turning roller 15 in a specified direction in parallel with the rotary shaft 21, and a control part for driving the page turning roller 15 in the way that the page turning roller 15 is moved in the specified direction by controlling the sliding mechanisms 20 and 24 according to the detection results of the detection means 17 and 18.