1. An electronic document classification system for classifying electronic documents received through a network, comprising: a criteria table for storing predetermined criteria for items included in the electronic documents; a score counter provided corresponding to each of the electronic documents; and a controller configured, for each of the items included in the electronic documents, to compare the item with a corresponding criterion stored in the criteria table, to obtain a score based on the comparison result, and to add the obtained score to the score counter; wherein the controller is further configured to assign a priority to each of the electronic documents in accordance with the value of the score counter corresponding to the electronic document.