A sheet processing apparatus including: a cutting mechanism, the cutting mechanism being configured to cut a sheet in a direction orthogonal to a sheet conveying direction by upper and lower cutting blades (22A, 22B) on the opposite sides of a sheet conveying surface, a pair of first conveying rollers arranged on the sheet conveying upstream side of the cutting mechanism and configured to feed the sheet to the cutting mechanism, a pair of second conveying rollers arranged on the sheet conveying downstream side of the cutting mechanism, characterised by driving sources configured to independently drive the pair of first conveying rollers, the pair of second conveying rollers, and the cutting mechanism, and a control section configured to control the operation of the driving sources, in which when sheet conveying direction length (Lr) of rear end cut region (Sr) of the sheet is equal to or more than predetermined value (Dn), rear end cut region (Sr) is sequentially cut and divided into predetermined fine-cutting unit length from the sheet conveying downstream end thereof, wherein when sheet conveying direction length of rearmost end divided region in rear end cut region (Sr) is equal to or more than minimum reference length corresponding to the distance between cutting position of the cutting mechanism and nipping position of the pair of first conveying rollers and is less than maximum reference length in which predetermined fine-cutting unit length is added to minimum reference length, the control section is configured to control the driving source to hold the upper and lower blades of the cutting mechanism opened immediately after the downstream edge of rearmost end divided region is cut and to drive the pair of first conveying rollers at a limited conveying speed lower than a normal conveying speed. a cutting mechanism, the cutting mechanism being configured to cut a sheet in a direction orthogonal to a sheet conveying direction by upper and lower cutting blades (22A, 22B) on the opposite sides of a sheet conveying surface, a pair of first conveying rollers arranged on the sheet conveying upstream side of the cutting mechanism and configured to feed the sheet to the cutting mechanism, a pair of second conveying rollers arranged on the sheet conveying downstream side of the cutting mechanism, characterised by driving sources configured to independently drive the pair of first conveying rollers, the pair of second conveying rollers, and the cutting mechanism, and a control section configured to control the operation of the driving sources, in which when sheet conveying direction length (Lr) of rear end cut region (Sr) of the sheet is equal to or more than predetermined value (Dn), rear end cut region (Sr) is sequentially cut and divided into predetermined fine-cutting unit length from the sheet conveying downstream end thereof, wherein when sheet conveying direction length of rearmost end divided region in rear end cut region (Sr) is equal to or more than minimum reference length corresponding to the distance between cutting position of the cutting mechanism and nipping position of the pair of first conveying rollers and is less than maximum reference length in which predetermined fine-cutting unit length is added to minimum reference length, the control section is configured to control the driving source to hold the upper and lower blades of the cutting mechanism opened immediately after the downstream edge of rearmost end divided region is cut and to drive the pair of first conveying rollers at a limited conveying speed lower than a normal conveying speed.