A questionnaire survey was conducted among 3,233 workers (2,442 males and 791 females) from 17 medium-sized business establishments in northern Japan with respect to GHQ-12 score, suicidal ideation, sociodemographic characteristics, work-associated factors, and attitude toward mental health resources. Sex differences were assessed for each questionnaire item, and logistic regression analyses were performed separately for males and females. Significant correlations between common mental disorder (CMD: GHQ-12 score≥3) and the following factors were found for both sexes: short sleep, irregular working schedule, working in specific businesses, and attitude toward mental health resources. Associations between CMD and excess workload were significant only in male workers. While correlations between suicidal ideation and demand for mental health resources were observed in both sexes, significant correlations were observed between suicidal ideation and use of mental health resources for female workers alone. These results suggest that screening of a high-risk population and provision of mental health resources contribute to suicide prevention as a part of mental health promotion measures in medium-sized business establishments. They also suggest the need for identification of business/job type-specific stressors while considering sex differences in lifestyle factors, working environment, and help-seeking behavior.