1. A method of determining a position of a deep brain stimulation (DBS) electrode, the method locating the position of the DBS electrode with respect to a targeted region in a deep brain of a living subject, by using a first volume data set of information on said targeted region and a second volume data set of information on said DBS electrode implanted toward said targeted region, the method comprising the steps of: generating a subvolume of the targeted region from the first volume data set of information on said targeted region, and also generating a subvolume of the DBS electrode from the second volume data set of information on said DBS electrode; and overlapping and displaying the subvolume of the targeted region and the subvolume of the DBS electrode.