A curl correcting device includes a pair of fixed guides and a change-over guide. The pair of fixed guides composes a curved part of a conveyance path. The change-over guide is provided to be contactable with a sheet from a radial outer side of the curved part. An outer guide includes a pair of side pressing parts and a bulge part. The pair of side pressing parts is formed at both ends in a width direction. The bulge part is formed between the pair of side pressing parts so as to bulge toward the radial outer side of the curved part. The change-over guide is configured to move to a first correcting position when the sheet curled along the conveyance direction is conveyed through the conveyance path and to move to a second correcting position when the sheet curled along the width direction is conveyed through the conveyance path.