In an image processing device, the memory stores conversion characteristic information corresponding to respective recording portions of an image recording device that records an image at a recording medium while moving a recording unit, which is provided with a plurality of the recording portions arrayed in a first direction, relative to the recording medium in a second direction that is perpendicular to the first direction, the conversion characteristic information expressing conversion characteristics for converting image data in units of one pixel. The first processing unit performs conversion processing along the first direction, continuously converting respective sets of pixel data aligned in the second direction, using conversion characteristic information that corresponds to the recording portions. The second processing unit performs image processing in the order of processing by the first processing unit. The output unit outputs the image data to the image recording device as aligned in the first direction.