A post-processing device comprising: a circulation conveyance path including: a first conveyance path (W1); a second conveyance path (W2); a third conveyance path (W3); a first conveyer (R1) configured to convey a preceding sheet (P1) from the first conveyance path (W1); a second conveyer (R2) configured to convey the preceding sheet (P1) along the second conveyance path (W2); and a third conveyer (R3) configured to convey the preceding sheet (P1) from the third conveyance path (W3) to the first conveyance path (W1), wherein the circulation conveyance path is configured to circulate the preceding sheet (P1) through the first conveyance path (W1), the second conveyance path (W2), and the third conveyance path (W3) in turn by the first conveyer (R1), the second conveyer (R2), and the third conveyer (R3); a zeroth conveyer (R0) configured to convey a following sheet (P2) toward the first conveyer (R1) in the first conveyance path (W1); and a controller configured to control operations of the zeroth conveyer (R0), the first conveyer (R1), the second conveyer (R2), and the third conveyer (R3), characterized in that the controller is configured to control the third conveyer (R3) to stop the preceding sheet (P1), subsequently control the zeroth conveyer (R0) and the third conveyer (R3) to overlay the preceding sheet (P1) with the following sheet (P2) to form a sheet bundle (Q) having a shift amount between a leading edge of the preceding sheet (P1) and a leading edge of the following sheet (P2) and strike the leading edge of the preceding sheet (P1) and the leading edge of the following sheet (P2) against the first conveyer (R1). a first conveyance path (W1); a second conveyance path (W2); a third conveyance path (W3); a first conveyer (R1) configured to convey a preceding sheet (P1) from the first conveyance path (W1); a second conveyer (R2) configured to convey the preceding sheet (P1) along the second conveyance path (W2); and a third conveyer (R3) configured to convey the preceding sheet (P1) from the third conveyance path (W3) to the first conveyance path (W1), wherein the circulation conveyance path is configured to circulate the preceding sheet (P1) through the first conveyance path (W1), the second conveyance path (W2), and the third conveyance path (W3) in turn by the first conveyer (R1), the second conveyer (R2), and the third conveyer (R3); a zeroth conveyer (R0) configured to convey a following sheet (P2) toward the first conveyer (R1) in the first conveyance path (W1); and a controller configured to control operations of the zeroth conveyer (R0), the first conveyer (R1), the second conveyer (R2), and the third conveyer (R3), characterized in that the controller is configured to control the third conveyer (R3) to stop the preceding sheet (P1), subsequently control the zeroth conveyer (R0) and the third conveyer (R3) to overlay the preceding sheet (P1) with the following sheet (P2) to form a sheet bundle (Q) having a shift amount between a leading edge of the preceding sheet (P1) and a leading edge of the following sheet (P2) and strike the leading edge of the preceding sheet (P1) and the leading edge of the following sheet (P2) against the first conveyer (R1). <EOS>