Abstract: An automatic focussing system including a photographic lens having a memory for storing informations (S0, A) concerning focussing of the photographic lens, a focus detecting unit for detecting a magnitude (d) of focus deviation of the photographic lens, an operation circuit for producing a magnitude of movement required to attain correct focussing of the photographic lens on the basis of the above-mentioned informations and the magnitude of focus deviation, and a driving unit for driving the photographic lens according to an output of said operation circuit, thereby attaining an optimum focussed state in a short time.