The study was performed by EMG. record of Parkinsonsism tremor and tremor-like movement of normal subject imitate to Parkinsonism tremor. H-reflex technique by electric stimulation on the posterior tibial nerve was combined. In grouping voltage of Parkinsonsism tremor as well as in voluntary tremor-like movement of normal subject, double discharge of the single NMU. was observed generally with a interval of 25 to 60 millisecond (ms.), and the double discharging unit was considered to be a kinetic NMU. H-reflex records in series by relatively long interval (low repetition) stimulation showed constant amplitude of H-reflex. But series by relatively short interval (high repetition) stimulation showed irregular amplitude, and by shorter than 30ms. interval stimulation H-reflex default at random. At some critical conditien e.g. 68ms. interval at gastrocnemius muscle, 95ms. at soleus mnscle the series of H-reflex showed two kind of amplitude., higher amplitude H-reflex and lower amplitude H-reflex appeared in each othor. Depending on the amplitude of repetitive M-reflex will not fluctuate even at short interval such as 20ms. as already described on other literatures, the auther would conclude that above mentioned fluctuation of H-reflex amplitude was caused by the character of the afterhyperpolarization of motoneuron. The paticular phenomen of amplitude fluctuation of H-reflex which appeared as higher amplitnde and lower amplitude in each other would be considered due to mixing existance of two kinds neuromuscular units those have shorter and longer hyperpolarization time, and those two kinds of units would adequate to kinetic and tonic neuromusclarunits.