This study investigates characteristics of burnout, as related to job descriptions in mental hospitals and presuppositions of the concept of burnout (burnout is caused as a result of having enthusiasm for a job). The results of a questionnaire survey (burnout tendency, Japanese Burnout Scale, enthusiasm for a job in the past, modified Enthusiasm scale) with 781 workers at mental hospitals showed that burnout characteristics varied according to job descriptions. Specifically, psychiatric social workers, medical assistants, and nurses fell into the high-burnout category, whereas doctors, occupational therapists, and pharmacists fell into the low-burnout category. In addition, in order to compare enthusiasm for a job in the past with current burnout tendencies, factor scores for the respective scales were classified into a low group or a high group and were cross tabulated. The numbers in the cells of the groups indicating the opposite of the definition of burnout (low enthusiasm-high burnout tendency, high enthusiasm-low burnout tendency) were larger. This indicates that having enthusiasm for a job is not a direct factor for burnout, which is different from the presupposition about burnout.