In an upcoming ubiquitous era, humankind will live in a ubiquitous space, where everything is connected through communication network. In this ubiquitous space, a ubiquitous robot, which can be used by anyone for any service through any device and any network at anytime and anywhere in a u-space, is expected to be required to serve seamless and context-aware services to humankind. In this paper, we introduce the ubiquitous robot, and define three components of the ubiquitous robot. The first one is "SoBot" which can be connected through the network in anywhere with environment recognition function and communication ability with human. The second one is "EmBot" which is embedded into environments and mobile robots and has localization and certification function with sensor fusion. The last one is "Mobile Robot" which serves overall physical services. This paper also introduces KAIST ITRC-Intelligent Robot Research Center that pursues the implementation of the ubiquitous robot.