This paper analyzes the conceptions and the mechanisms of trust, both institutional and interpersonal, in a long term customer/bank relationship. A qualitative and longitudinal study was adopted, based on 18 retrospective case studies conducted within a French bank. Each case focuses on the relationship between a customer and his financial adviser, at the time when the study was carried out. Further, we analyze the conceptions of trust from the two perspectives of the customer and of the financial adviser. The results have important implications for understanding the different meanings and mechanisms of institutional trust and interpersonal trust in the customer/bank relationship.