To explore work stress–strain relations and the effect of Type A/B personality among Japanese adult employees, a questionnaire survey was conducted in two branches of a large bank in Hokkaido, Japan. Data were obtained from 256 adult employees (158 males and 98 females). The questionnaire consisted of several scales concerning role stress, the 28‐item General Health Questionnaire (GHQ‐28), job dissatisfaction, the Jenkins Activity Survey, and others. While most of the variables differed across three subsamples (male clerks, males of chief clerk status or higher, and female clerks), both role overload and conflict were comparable. Role overload and conflict were highly associated with psychological distress, but role ambiguity showed a few significant correlations. Also, fewer significant correlations were found for Type A/B subscales. A moderated multiple regression analysis was carried out by subsample for each pair of role stress and Type A/B subscale for each psychological distress. A buffering effect of Type A/B was tested by considering the significance of its interaction term with role stress. As a whole global A tendency ie, high scores on the JAS‐A/B subscale would play a role as ‘buffer’, but high hard‐driving and competitive tendencies would play roles as both ‘buffer’ and ‘exaggerator’ according to the type of stress. Most of these results, however, were detected in the analyses of male clerks. Therefore, either buffering or exacerbating effects of Type A/B personality on stress–strain relations were recognized to vary between genders, across job positions, and/or across the types of stress at work and distress.