A plurality of targeted ion characteristics and a charge reduction amount are received. With the base unit 1 resting on the housing or the base table, the camera holder 2 is rotationally movable relative to the base unit 1 at least in a vertical direction X, and the camera unit 3 is rotationally movable relative to the camera holder 2 at least in the vertical direction X. A control paneldisplay is connected to the microcomputer and includes a pair of monitors for displaying target loads andor actual loads averaged over a number of gait cycles for each foot.