There are many studies on depression in middle-aged people, but few studies on oral health and depression. Therefore, the purpose of this study is to investigate the relationship between oral health-related factors and depression in adults aged 40 to 60 years. In this study, cross-sectional analysis was used to investigate the relationship between demographic factors and depression in middle-aged adults and the relationship between depression and oral health factors in middle-aged adults. Key finding of the present study included. First, Middle-aged adults showed more depression when they were female, economically active, and less educated. Second, The time when depression was diagnosed is 41~60 years old (62.8%) applicable to the middle age and it was surveyed 58.5% did not take treatments after diagnosed as depressed. Third, In the relationship between oral health factors and depression in middle-aged adults, the prevalence of depression was high when they experienced toothache, chewing problems, and mental discomforts during the last year. Since oral health factors in middle-aged adults can affect depression, which can negatively affect quality of life, basic data can be developed to increase motivation and interest in oral health in middle-aged adults. It is expected to be utilized.