There are some studies which applied a function of pattern separation to technical systems. The effect of its function on an associative memory system, however, has not yet been clarified sufficiently. In the present paper, a new associative memory model having the function of pattern separation is given, and its ability of recall is derived. The ability is compared to that of the traditional model. As the result, it is shown that the model is superior to the traditional model with respect to the recalling ability. Further, it is also cleaned up that the ability of recall in the model is enhanced by the function of pattern separation.