Causes of beach erosion on the southern Ishikawa coast facing the Sea of Japan was investigated based on the history of local area. In this area, the shoreline has been retreating, and in the previous studies the cause was said to be due to the offshore sand movement. However, in this area sand mining has been extensively carried out at and around the shoreline as well as dredging at two river mouths, where river mouth closure was severe. Thus, artificial causes cannot be ignored as the causes of beach erosion.