An object position detecting method and apparatus whereby even an image subjected to deformation such as shift, rotation, scaling, etc., can be recognized with high accuracy. Also disclosed is an image processing system that uses the object position detecting method and apparatus. The object position detecting apparatus is composed of an image input device (5), a Fourier transform device (6) for performing Fourier transform on an input object image, a reference beam device (7) for generating a reference beam, a recording device (8) for recording a wavefront formed by interference between the Fourier transform information on the input object image and the reference beam, thereby producing a Fourier transform hologram, a read device (9) for reading the recorded Fourier transform hologram by using the Fourier transform information on the input object image, an inverse Fourier transform device (10) for subjecting the read information to inverse Fourier transform, and a detecting device (11) for detecting the information having been subjected to the inverse Fourier transform, thereby obtaining the position of the object to be recognized.