Provided is a paper sheet replenishing box (paper feed device) for replenishing reserve fund in each circulation-type paper sheet storage unit, wherein paper sheets of each denomination can be replenished from one paper sheet replenishing box in which paper sheets of different denominations having different sizes are accommodated together to a circulation unit of the respective circulation-type paper sheet storage units. The paper sheet replenishing box includes a first tray piece 201 in which a plurality of pieces of first paper sheets P1 are placed in a stacked state, a second tray piece 211 arranged immediately below the first tray piece, on which a plurality of pieces of second paper sheets P2 having a different longitudinal dimension from that of the first paper sheet are placed in a stacked state, and rear-end regulating members 204 and 214 that align front end positions in a transport direction of respective paper sheet bundles to predetermined positions. After all the first paper sheets in a bundle on the first tray piece have been fed by a feed unit 160, an uppermost surface of the second paper sheets in a bundle on the second tray piece becomes a state capable of coming in contact with the feed unit.