Sheet processing apparatus

A sheet processing apparatus comprising:

• a transport section transporting a sheet;
• a processing tray section having a sheet mounting surface on which the transported sheet is mounted and a processing section that performs processing on the sheet;
• a side edge alignment section that is provided on the processing tray section and aligns a side edge of the sheet;
• a lower support section that is provided downstream of the processing tray section in a transport direction of the sheet and supports the sheet from below;
• and
• a discharge tray located below the lower support section in a sheet stacking direction orthogonal to the sheet mounting surface of the processing tray section, wherein
• the side edge alignment section performs a shift operation of shifting the sheet in a shift direction orthogonal to the transport direction of the sheet, and
• the lower support section moves in the shift direction in conjunction with a movement of the sheet in a state of supporting the sheet from below during the shift operation by the side edge alignment section.