Image processing apparatus and image processing method

A pixel that is a target pixel being a processing target of a first multi-valuing unit is regarded as a first target pixel. A pixel that belongs to a pixel row adjacent to the pixel row to which the first target pixel belongs in the image data before conversion and is a target pixel being a processing target of a second multi-valuing unit is regarded as a second target pixel. A conversion unit converts the pixel array in the image data so that the first target pixel and the second target pixel are stored at serial addresses in a memory. An error diffusion processing unit performs multi-valuing by the first multi-valuing unit for the first target pixel in the image data after conversion and multi-valuing by the second multi-valuing unit for the second target pixel in the image data after conversion in a parallel manner.