An image processing apparatus includes: a dividing unit dividing at least one region on a digitalized image into multiple blocks; a scrambling unit producing an encrypted image by rearranging each block; a pixel value judging unit judging, for each block on the encrypted image, whether a difference between a statistically representative value of a pixel value of a first region included in the block and a statistically representative value of a pixel value of a second region is no smaller than a predetermined value, the second region being included in a block adjacent to the block and being adjacent to the first region; and a pixel value converting unit converting the pixel value of the first region in each block having the difference smaller than the predetermined value, while not converting the pixel value of the first region in each block having the difference no smaller than the predetermined value.