(Problem to be Solved)To appropriately restrain occurrence of striped variation and to appropriately enhance image quality of a printed result.(Solution)An inkjet printer in which multi-gradation printing is performed in an inkjet method includes an ejection control section for controlling ejection of ink droplets by supplying an ejection control signal to a nozzle for controlling ejection of the ink droplets from the nozzle of an inkjet head. The inkjet head forms lines of ink dots juxtaposed in a line direction so that the lines are juxtaposed in a direction perpendicular to the line direction. In a case that a nozzle which forms a line is the abnormal nozzle, an ejection control signal corresponding to an ink dot size which is different from a case of the normal nozzle is supplied as the ejection control signal corresponding to a part of the dots juxtaposed in the line, thereby an average value in the line of ejection errors is brought close to zero.