A curl correcting unit can be attached in a normal orientation and inverse orientation. In the normal orientation, a sponge roller being on the lower side, a sliding plate is pressed down by a curl-correction-amount adjusting mechanism. When the sliding plate is pressed down, a roller-side plate is lifted up via a link, where the link works as a shaft of a seesaw that connects the sliding plate and the roller-side plate. As a result, the sponge roller moves up and comes into press-contact with a metallic roller. In the inverse orientation, the sponge roller being on the upper side, the roller-side plate is directly pressed down by the curl-correction-amount adjusting mechanism and thereby the sponge roller comes into press-contact with the metallic roller.