The aim of this study was to show Japanese educating practice of skin care for radiodermatitis of breast cancer outpatients. 321 curative facilities in total were chosen from 296 facilities belonging to Japanese Society for Therapeutic Radiology and Oncology (JASTRO) and 114 facilities that Certified Nurses in Radiation Therapy Nursing (CN) belong to, excluding overlapping facilities. Subjects of this question were nurses doing radiotherapy (RT) of outpatients. One nurse chosen by each facility answered the questionnaire survey for instruction of skin care about timing RT. We divided the nurses into CN and NS groups, and analyzed all the collected data by using the chi-square test, and compared nursing practice of the CN with that of NS. The ratio of CN ［washing irradiated site using soap during RT］ was significantly higher than NS. The ratio of CN［ washing irradiated site using mild soap］ and ［lathering the foam when using soap］ was significantly higher than NS. From comparing nursing practice of the CN with that of NS, it was shown that the CNs were practicing skin care based on recommended skin care for radiodermatitis by literatures.