Disclosed is an image processing apparatus that makes it possible to conduct an operation for correcting density unevenness in a main-scanning direction of an image, while achieving both the accuracy and the efficiency thereof. The image processing apparatus includes: an outputting section to output data representing a test chart including a plurality of patches respectively having different gradation values and extended in the main-scanning direction; an acquiring section to acquire a measured result of measuring a density of each of the patches included in the test chart printed on the basis of the data outputted by the outputting section; and a control section that compares the density unevenness of a pair of patches being adjacent to each other and deriving from the measured result, so as to determine new data representing a next patch to be outputted on a next occasion, based on a comparison result thereof.