In order to enable a sheet end portion to be properly guided to a nip portion in performing folding processing a plurality of times, provided are a transport path including a guide face to guide a transported sheet, a rotating body pair which nips the sheet transported to the transport path by a nip portion to rotate, a folding blade that pushes the sheet to the nip portion of the rotating body pair, and a blade guide member including a guide portion for pushing one end of the sheet to the nip portion when the folding blade pushes the sheet to the nip portion, and a shift section that shifts the folding blade and the blade guide member in a push direction for pushing to the nip portion and in a return direction opposite to the push direction.