Recently, it has been recognized that vibration diseases among vibrating tool operators are hazards not only to one part of the body but also to the body as a whole. Therefore, questions related to general subjective symptoms have been incorporated into the questionnaire given in connection with the examination of vibration diseases. In the case of forest workers who operate chain saws, it is not satisfactory that the amount of vibration suffered by them is represented only by occupational history i.e. the number of years they operated the saw, because there is much difference among chain saw operators, as regards the number of hours/day or days/year during which they actually operated the saw. In this paper, the amount of vibration suffered by them was calculated according to the total operating time which was the chain saw operating hours/day × days/year × years. Civil forest workers in Wakayama Prefecture in Japan were surveyed concerning vibration diseases from March to May in 1975. The questionnaire included all the items laid down by the Labor Ministry directions concerning surveys of subjective symptoms, and rates for all these items were worked out for 214 forest workers who did not operate any vibrating tools and 720 chain saw operators. For 628 of the 720 operators, it was possible to calculate the total operating time of chain saws. The 214 workers and 628 operators were divided into 6 groups by total operating time as follows : 0hr group (214 workers), 0-1, 000hr group (131 operators), 1, 000-2, 500hr group (143), 2, 500-5, 000 hr group (158), 5, 000-7, 500hr group (84) and above 7, 500hr group (112).Symptom rates were calculated for each group respectively. The progress of and changes within each symptom were studied in each group. The results are as follows : 1. All subjective symptom rates of chain saw operators were higher than those of forest workers who did not use vibrating tools. 2. Typical symptoms of chain saw operators were white fingers, stiffness of hands, numbness and pain of fingers and arms, fatigue, dullness, chills, sensitiveness to cold, gastric disorders, sexual disinclination, heart acceleration and difficulty in breathing. 3. Early symptoms of chain saw operators were fatigue, numbness of arms, numbness of fingers and chills. 4. Chills were considered as a prodromal symptom of numb fingers and white fingers. 5. Most of the symptoms had a tendency to increase in rate in cases above 1, 000hr of total operating time of chain saw. 6. Almost all symptoms rates of sympathetic nervous system were remarkable in cases above 2, 500hr of total operating time of chain saw.