A first longitudinal registration correcting unit corrects a misalignment of a recording medium in its conveying direction. A lateral registration correcting unit corrects a misalignment of the recording medium in its width direction after the misalignment in the conveying direction is corrected by the first longitudinal registration correcting unit. A second longitudinal registration correcting unit corrects the misalignment of the recording medium in the conveying direction again after the misalignment in the width direction is corrected by the lateral registration correcting unit.