To provide a sheet processing device capable of facilitating counting operation of the number of sheets and dividing operation of the sheet bundles in an intermediated stacking position by easily determining a border between the cut and stacked sheet bundles.

A sheet bundle is formed by superposing sheets on an alignment longitudinal path 35. A gluing unit 25 is moved along the lower face of the sheet bundle to glue the lower face of the sheet bundle on a surface sheet. The glued sheet bundle is received by a rotating stage 301 and carried to a cutting part 90 by the rotating stage 301 to cut and align the side faces of the sheet bundle. In the cutting part 90, by using an uneven cutting edge, the three side faces of the sheet bundle are decoratively cut. The sheet bundle of which side faces are cut and aligned by the cutting part 90 is delivered to a stacking tray E by the rotating stage 301 and stacked.