Body sways can be evaluated with several parameters by posturography. In order to recognize body sway more precisely and to clarify the difference in findings between normal persons and patients with equilibrium disturbance, various parameters must be treated comprehesively. The author studied the above mentioned difference and obtained the following results. 1. A program for analysis of posturography is developed in which the output of signal from strain-gauze is sent through an A/D converter into an NEC PC 9801 E computer and the recordings are stored in floppy discs. 2. Area, length, deviation, velocity and frequency were examined in normal persons and in patients with equilibrium disturbance. Especially, the analyzed results of frequency are expressed in powerspectrogram (PSG) so that the results can be used in evaluating practical cases. 3. To comprehend body sway, point system is devised and marks are given according to the results of each parameter. Four categories eg. sway score, Romberg score, deviation score and PSG are combined collectively for a comprehensive evaluation of body sway.