A sheet processing apparatus including a table to be loaded a first and a second banknote group partitioned by a header card recording the bar code number in the piling direction of the banknotes, a take-in portion to take in the banknotes of the first and second banknote groups loaded on the table and the header card, a discrimination portion to count the banknotes taken in by the take-in portion and discriminate the kind thereof, a plurality of stackers to sort and stack the banknotes discriminated by the discrimination portion on the basis of the kink thereof, and a sensor to detect the header card taken in by the take-in portion. The sheet processing apparatus additionally includes a controller to control so as to stop the taking-in of the second banknote group on the basis of detection of the header card by the sensor and after a lapse of a predetermined time, to start the taking-in of the second banknote group.