A neighbor cell list optimizing system according to the present invention is a neighbor cell list optimizing system that updates a neighbor cell list that is provided in a base station that manages a cell to which a mobile terminal establishes a connection and to which specific neighbor cells that are candidates of a handover destination cell for said mobile terminal of neighbor cells that are in the vicinity of said cell are registered, comprising: priority computation section that computes priorities of said neighbor cells to be registered to said neighbor cell list based on measurement information that represents radio communication qualities of neighbor cells in which the measured radio communication qualities exceed a threshold; and neighbor cell list updating section that registers neighbor cells in descending order of the priorities up to an upper limit of radio cells that can be registered to said neighbor cell list.