According to one embodiment, a sheet processing device includes a jogger fence configured to carry out a crosswise direction alignment to a stack of image formed sheets ejected from an image forming apparatus, a rear end fence acting as a lengthwise reference edge, a stapling device configured to staple the aligned sheet stack, a discharge belt configured to move the stapled sheet stack to a sheet ejection tray, and a controller to control movement of the jogger fence during the sheet stack being moved by the discharge belt so as to move the jogger fence more than once between a position where the jogger fence does not contact the edge of the sheet stack and a position where the jogger fence pressing contact the edge of the sheet stack.