Conventional work motivation theories have focused on tasks that require a certain level of performance and achievement. However,it is not clear what kind of psychological process would improve work motivation for performing jobs in which such performances and achievements are not presupposed. By focusing on social contribution,this study aimed to clarify the psychological process to improve work motivation of jobs in which do not require objective or concrete performances and achievements. A survey was conducted on 179 operators from 6 call centers. The questionnaire comprised items on sense of social contribution,feedback from supervisor,work motivation,and work behavior with consideration for the customer. The results showed that the sense of social contribution to customers and to organization mediated the association between positive feedback from supervisors and work motivation. However,negative feedback from supervisors did not have a significant relationship with sense of social contribution and work motivation. These results suggest the importance of enhancing the experience of a sense of contribution to others through the provision of positive feedback while managing jobs in which do not require objective or concrete performances and achievements.