Purpose: The purpose of this study was to identify factors affecting early detection behaviors of breast cancer such as breast self examination(BSE), breast physical examination, mammography. Method: The subjects were 141 women on an island and materials were collected through an organized questionnaire from March, to August 2002. The data were analyzed by using descriptive statistics, $x^2$ and logistic analysis by SAS program. Results: 52.7% of the subjects performed breast self examination, 67.2% did breast physical examination and 67.7% did mammography. That is, about 60% of the subjects performed early detection behavior to find the breast cancer. Practice of breast self examination was significantly correlated with experience of physician examination and mammography. The most significant factor on BSE was a normal salted diet, and the most significant factor on physical examination and mammography was the high education level of subjects. Conclusions: According to the results of this study, it suggests that intensive education and information strategies for breast cancer early detection need to be developed. In particular, early detection programs for lower educated women should be activated.