An image processing apparatus which converts first image data having grayscale value of a predetermined color space for each pixel into second image data having grayscale values of recording material colors of a printing section and having pixels of which the number is reduced to 1/n, includes grayscale value difference determination section that determines whether or not grayscale value difference between a predetermined target pixel and each of other pixels in a pixel block exceeds a threshold value for each of the pixel blocks for the first image data, and color conversion section that performs color conversion process by referring to color conversion table, and color conversion section performs a second process such that grayscale value of the recording material color obtained through color conversion process for an average value of grayscale values of the predetermined color space of the respective pixels is used as the second image data.