Recently, information recorded on paper has been changed rapidly to digital data. Backup systems emphasize prevention of data loss by disasters, mistakes of user operations, and so on. For robust backup, it is necessary that the data be distributed geographically. Using a distributed backup system, the possibility of all data becoming lost will definitely be low. However, several problems with distributed backup systems remain. First, preparing multiple computers is expensive. Second, the computational cost of encryption and redundancy is high. Third, user workloads necessary to manage and maintain the system are great. As described herein, to overcome those problems, we propose a distributed backup system using multi-agent technology. The agents can work autonomously depending on the environment. We first show a design of the promptitude tpe agent in a contemplation type agent framework. Then we present the results of experiments.