The purpose of this study is to develop a quantitative measure of the bradykinesia which can be conveniently used during clinical motor examination (finger taps, forearm pronation/supination, foot-taps) in patients with Parkinson's disease. Forty Parkinson's disease patients, 14 age-matched elderly subjects and 17 healthy young subjects participated in the experiments. Severity of bradykinesia in both right and left side were rated by two independent neurologists according to the unified Parkinson's disease rating scale (UPDRS). Angular velocity of finger forearm and foot during clinical rating was measured by the gyrosensor system and action tremor was eliminated. As quantitative measures, root-mean-squared (RMS) angular velocity, RMS angle, peak power and total power were used. ANOVA showed that all measures in all three examinations are significantly different among three subject groups (p<0.001). The spearman's rho between the suggested measures and UPDRS score was -0.730~-0.780 for finger taps, -0.609~-0.836 for forearm pronation/supination, -0.689~-0.825 for foot taps. The results suggest that the indices from a gyrosensor can be used as quantitative measures of bradykinesia during several clinical motor examinations.