This paper describes a “Ubiquitous Personalize Agent” and it’s application: “Shopping assistance service” for ubiquitous environments. Ubiquitous personalize agent is realized based on context reasoning technology. It can determine contexts of users by referring a lot of data which can be retrieved from devices in ubiquitous environments. We also have had an experimental trial of this service. In this paper, we state the technology, service, and evaluation on the experimental trial.