In the provision of bespoke services, a good salesman usually selects the best sales technique based on his observations of the behavior and mental state of the customer. However, it is difficult for an inexperienced staff member to accurately grasp the actual conditions. By repeating the training with the feedback on customer’s mental state, the salesman is supposed to get a better understanding of the customer’s mental state and choose the most appropriate sales technique. This study is a preliminary study for the development of the sales skills training support system mentioned above. Using electrodermal activity (EDA), we analyzed the psychological activities of the customers who were customizing suits. We recruited ten male customers in the custom‒made suit shop to participate in our experiment. Their EDA was measured by watch‒type sensors in the customization process. Additionally, the customers’behaviors were recorded by two cameras at the same time. It has been suggested that EDA could be applied to the measurement of psychological activities for bespoke services. EDA responses were confirmed at several key points in the customizing process. In particular, we found that EDA response appeared when the customers encountered “conflict” with the choice of options, “deciding” on an option, or “imagining” the appearance of options.

　　As a result, we proved that EDA can indicate the timing of the emotional changes that take place in the customization process. Providing feedback on customers’EDA information to sales clerks could show them the key points of the conversation immediately, which is considered helpful in selecting the most appropriate sales technique. In the future, the proposed feedback system will be constructed and the impact on sales clerks will be investigated as well.