An image processing apparatus includes a plurality of cores that carry out binarization processes while shifting a target pixel from the first pixel in a processing line in order toward the last pixel in the processing line in accordance with a diffusion of error that takes unprocessed pixels surrounding the target pixel including the pixels of the following line of the processing line as a diffusion range; of the plurality of cores, the core that processes the following line carries out the binarization process in order while delaying the target pixel at least by an amount equivalent to the diffusion range relative to the target pixel of the core that processes the previous line. Accordingly, the lines can be processed in parallel while reflecting the error appropriately on the unprocessed pixels, and thus the binarization process using error diffusion can be carried out more quickly.