The purpose of this research was to analyze four factors of addicted cell phone use affecting mental health. The participants were 639 second graders, who were selected among eight middle schools in Jeju Province in Korea (Republic) by the multiple cluster sampling. The questionnaire was administered to measure participants’ addicted cell phone use and mental health, and the collected data were analyzed by Regression and Correlation Analysis. The results were that the four factors (Tolerance-dependency, Cling, Life-distress, and Obsession) were significantly correlated with mental health. The results indicated the more addictively students use their cell phones, the lower levels of mental health they have in the case of Korean middle school students. This research suggests that the guidance from teacher and parents for adequate cell phone use would improve adolescents’ mental health.