An image processing apparatus includes a predictive picture generator configured to generate a predictive picture for an encoding target block based on pixel values of pixels included in already-encoded blocks around the encoding target block, a predictive error generator configured to generate predictive error based on a picture expressed by the encoding target block and a weighting unit configured to apply weights to pixel values by conducting a multiplication that multiplies by a constant greater than 1 the pixel values of pixels used to generate a predictive picture for another encoding target block, the pixels being pixels from among a plurality of pixels included in predictive error generated by the predictive error generator.