The study of farmers’ mental health according to their production model (organic vs. conventional) suggests that organic farming was associated with better mental health than conventional farming. However, to our knowledge, no research has been conducted to examine the social psychological factors responsible for these differences. This research aims to investigate the role of job content and values on farmers’ mental health according to their production model. To this end, an online questionnaire study on these dimensions was conducted on a sample of farmers. The results revealed that organic farmers scored significantly lower in anxiety and higher in positive emotions than conventional farmers. Psychological demand and conformity value appeared to be the most important explanatory factors related to the effect of farmers’ production model on mental health. Implications for the response rate and farmers’ mental health were discussed.