A sheet reversing device has a vertical first conveyance path, a horizontal second conveyance path into which a sheet is carried via the first conveyance path and a horizontally third conveyance path into which the switched-back sheet is carried from the second conveyance path. A curved guide plate is disposed between the first and second conveyance paths and includes a curved guide surface for guiding the sheet to the second conveyance path, and a pivotal guide pivotably supported with a part thereof projecting from the curved guide surface. The pivotal guide pivots to retract into the inner side of the curved guide by being pushed by the sheet moving from the first conveyance path toward the second conveyance path while guiding the sheet switched back and carried out from the second conveyance path toward the third conveyance path with the part thereof projecting from the curved guide surface.