A prediction method generates a fragment number map having a predetermined number of pixels and a mipmap of the fragment number map, and for a pixel of one layer in the mipmap, derives an estimated number of fragments included on average on one light path in a case where ray-bundles for a light transport computation are defined for a corresponding region in a 3D scene corresponding to the pixel, and outputs, as a predicted number of ray-bundle light paths for the computation storable in a predetermined memory region for a pixel of one layer, a value obtained by dividing the size of the memory region by this value. The method derives an estimated number of fragments by adding a compensation value corresponding to a layer of the pixels in the number of fragments which is a pixel value of one pixel.