Insuring fast and precise human operation is one of the engineering requirements in the developing civilization.
Some man-machine system, when any operator is exposed himself to some kind of vibration, he may not perform his operation in good conditions. Then one of the interferring factors, there is a fatigue caused by vibration. In this study, subjects sit on the chair which was set on the vibration table, and were shaken vertically for some given times, then were measured whether the fatigue occured or not by flicker friction tester. Flicker patterns were analyzed according to each vibration-condition, then the authors knew that the fatigue was occured by vibration.