Purpose: This study aims to find the mental health characteristics and factors affecting depressive symptoms in military social service personnel.Methods: This descriptive investigation retrospective cohort study analyzed secondary data of social service personnel at I City for five years from April 2016 to May 2020. The Center for Epidemiological Studies-Depression Scale, the Alcohol Use Disorder Identification Test-K, the Paranoia Scale, and the Reynolds Suicidal Ideation Questionnaire were used to examine the mental health of social service personnel.Results: Compared to the military social service personnel with no depression, depressed social service personnel were more paranoid (t=7.13, <i>p</i><.001), and had more suicidal ideas (t=7.44, <i>p</i><.001). Depressive symptoms had a significant positive correlation with alcohol use disorder scores (r=.262, <i>p</i><.001), paranoid ideas (r=.594, <i>p</i><.01), and suicidal ideas (r=.594, <i>p</i><.01). Alcohol use disorder scores (β=.16, t=2.86, <i>p</i>=.005), paranoid scores (β=.30, t=4.34, <i>p</i><.001), and suicidal ideas (β=.42, t=5.95, <i>p</i><.001) predicted depressive symptoms (R<sup>2</sup>=.49, <i>p</i><.001).Conclusion: Alcohol addiction, paranoid ideas, and suicidal ideas were found to be factors that affect depressive symptoms in military social service personnel.