A sheet processing device includes: a first reservoir unit which reserves sheets; a sheet processing unit which implements predetermined processing for the sheets reserved in the first reservoir unit; a discharge unit which includes a stepping motor, and discharges the sheets from the first reservoir unit, the sheets being subjected to the predetermined processing by the sheet processing unit; an obtaining unit which obtains a value regarding weight of the sheets subjected to the predetermined processing; and a control unit which controls the discharge unit to lower a rotation speed of the stepping motor in a case where the value obtained by the obtaining unit is more than a predetermined value in comparison with a case where the value is less than the predetermined value.