Abstract: A paper sheet processing device includes: a receiving part which opens to an exterior of the device, in which paper sheets from the exterior of the device are set, and which dispenses the set paper sheets in a stacked state, one by one; a conveyance unit which conveys the paper sheets dispensed from the receiving part; an identification unit which identifies whether the paper sheets that are being conveyed by the conveyance unit are a to-be-counted paper sheet or a reject paper sheet; a post-count accumulating part which accumulates a paper sheet identified as the to-be-counted paper sheet; and a plurality of reject accumulating parts which accumulate, in a state sorted by reason for rejection, a paper sheet identified as the reject paper sheet.