The effect of tremor suppressor is studied. The tremors during writing with or without the tremor suppressor called as palm supporter are measured. The sensor is attached to the back of the hand. The sensor detects three dimensional acceleration. Power spectra of three dimensional acceleration are evaluated as SQRT in unit of G2. Subjects are old person with “essential tremor” and “Parkinson’s tremor”. Their ages are 69 to 85 years old. For comparison, subjects of healthy old person are studied. The kinds of writing are vertical line, horizontal line, circle and Chinese characters. Subjects write each kind of writing every 10 times. The results of healthy old person and persons with Parkinson’s tremor show no effect of tremor suppressor. On the other hand, the results of persons with essential tremor show the effect of tremor suppressor. Large effect for writing of horizontal line is specially recognized.