Provided is a sheet processing apparatus, including: a stacking unit that is capable of stacking discharged sheets; a drive mechanism that is capable of moving the stacking unit; a storage device that holds data on a moving time of the stacking unit in a rewritable manner; an arithmetic unit that is calculates an estimated value of the moving time of the stacking unit based on the data; and a correcting unit that corrects the data held in the storage device by using an actual measurement value of the moving time of the stacking unit.