A decurling mechanism for performing a decurling process of correcting the curl of paper includes: a first roller; a second roller disposed travelably around the first roller; and a roller position changing mechanism for changing the second roller to a plurality of positions set on a traveling path of the second roller. The plurality of positions include a decurling position in which the decurling process to the paper is enabled and the paper is conveyed while being pinched between the first and second rollers, a conveyance position in which the decurling process to the paper is disabled and the paper is conveyed while being pinched between the first and second rollers and a pinch release position in which the paper is released from the pinch between the first and second rollers.