a first conveyance path through which a sheet is conveyed;

a reverse roller pair configured to convey the sheet conveyed from the first conveyance path in a first direction and reverse the sheet toward a second direction opposite to the first direction;

a second conveyance path through which the sheet reversed by the reverse roller pair is conveyed in the second direction;

a conveyance roller pair disposed in the second conveyance path and configured to nip and convey the sheet in the second direction;

a supporting portion which is positioned downstream of the conveyance roller pair in the second direction and on which the sheet discharged in the second direction from the second conveyance path by the conveyance roller pair is supported;

a regulator configured to come into contact with a leading edge of the sheet in the second direction to regulate a position of the sheet on the supporting portion;

a sheet processor configured to process the sheet supported on the supporting portion and move in a direction along the second direction;

a discharge portion through which the sheet processed by the sheet processor is discharged out of the sheet processing apparatus;

a third conveyance path extending from the supporting portion toward the discharge portion; and

a guide configured to move in a third direction to push the leading edge of the sheet from the supporting portion toward the discharge portion through the third conveyance path, the third direction being opposite to a direction in which the leading edge of the sheet approaches the regulator when the sheet is discharged in the second direction by the conveyance roller pair,

wherein the discharge portion is positioned downstream of a movement region of the sheet processor in the third direction, and

wherein the sheet processor is a stapler configured to staple a plurality of sheets stacked on the supporting portion to form a sheet bundle.