To provide a small bank book processing device of a simple structure securely preventing the generation of turning over of a plularity of pages of a bank book.

An image sensor 12, a printing mechanism 11, a thickness sensing mechanism 13 and a page turnover mechanism 9 are set along a carrying line 14, and a turnover roller 32, a press roller 41, a feed roller 37 and a press roller 40 are disposed at the interval of the length of a page on one side of a bank book 2 on the page turnover mechanism 9. The bank book page is read and grapsed by an image sensor 12 of a control section/driver 62 before turning over the page of the bank book 2, and a turnover page memory 20 and a carrying motor 21 are controlled in compliance with the page of the bank book when the turning-over of the page is carried out so that the bank book 2 is carried to an optimum page turnover position in compliance with the page of the bank book by the turnover roller 32 and the feed roller 37 and stopped thereon, whereon the page is turned over.