A liquid jetting apparatus includes a recording head unit including nozzles; a moving mechanism configured to alternately perform a scanning operation of moving the recording head unit in a scanning direction while causing the recording head unit to discharge a liquid and a sub-scanning movement operation of moving the recording head unit or the recording medium in a sub-scanning direction without causing the recording head unit to discharge the liquid; a gradation setting unit configured to set gradation on portions of image data corresponding to setting regions at ends of the recording head unit; an irregular pattern setting unit configured to set an irregular pattern on the image data to randomize a dot ratio indicating the number of dots per unit area; and a head discharge drive unit configured to cause the nozzles to discharge the liquid based on the image data.