In a first step, a sheet is conveyed in a direction, whereby a leading end portion of the sheet is fed to a position between a decurl roller and a decurl pinch roller, which are in positions spaced apart from each other. In a second step, the leading end portion of the sheet is curved and held by causing the decurl pinch roller to come close to or press against the decurl roller. In a third step, the leading end portion of the sheet is withdrawn from between the decurl roller and the decurl pinch roller by conveying the sheet in a direction opposed to the conveying direction. After executing the first to third steps, the sheet is conveyed in the conveying direction through the first step while the sheet is curved by the decurl roller.