1. A method for shooting an original by an image shooting apparatus having a photoelectrically converting device and a scanning mechanism, said method comprising the steps of: directing one by one split images of the original including overlapping areas to the photoelectrically converting device by operations of the scanning mechanism; shooting the directed split images by the photoelectrically converting device; detecting a degree of the operation of the scanning mechanism every directing by the scanning mechanism; extracting an effective image from each of the split images based on the detected degree; and connecting the extracted effective images in order to complete an image of the original.