There was not a detailed trouble-support manual for the most popular 8 MHz. RF capacitive heating device in Japan. Now each institution devises the troubles and performs hyperthermia. In Tobata Kyoritu Hospital Cancer Therapy Center, we made a support manual in case of a trouble during hyperthermic treatment. At a trouble during hyperthermia, we could respond quickly with unified recognition regardless of the years of experience with use of the manual. This manual also was able to utilized for the engineer education, hereby, we were able to succeed to offer safe treatment.