A booklet making method includes: cutting a web of paper on one side and on another side into first and second continuous sheets, alternately bonding the first and second continuous sheets widthwise with a setting paste and a throwaway paste to form a double set continuous sheet of paper, and cutting the double set continuous sheet of paper into split double sheets of a selected longitudinal length. A plurality of split double sheets is integrally bound with an integrating paste to form a booklet-like product. Portions of the booklet-like product which are pasted and bonded with the throwaway paste are cut off to provide a plurality of booklets. Thus, by the booklet making method, booklets having an odd number of leaves or pages are formed without waste of paper and with reduced paper jams.

The present invention is to provide a sheet processing device including: a receiving tray capable of accommodating therein a sheet having, at a part thereof, a protruding portion and a sheet not having the protruding portion in a mixed state; a first binding member that binds the accommodated sheet bundle at a substantially center thereof in a sheet conveying direction; a folding section that folds the sheet bundle bound by the first binding member in two; and a second binding member that binds protruding portions of the sheet bundle folded by the folding section on a fore edge side of the sheet bundle. With this configuration, the fore edge side of the folded and saddle-stitched sheet bundle can be bound by temporary binding. Thus, a sheet processing device capable of ensuring the security of a saddle-stitched sheet bundle can be provided.

A staple-less binding unit 27 is disposed between a front cover 121 and a sheet stacking table 16, and an insertion port 110 is formed on a first surface 121a of the front cover 121 so that manual binding by the staple-less binding unit 27 can be executed from the front side of the apparatus. The staple-less binding unit 27 is provided at a position overlapping a stapling unit 17 positioned at a replacement position in a front-rear direction.