Intelligent spaces based on many networked sensors have been studied in recent years. In this study, a mobile intelligent space using a human-following robot is considered. The proposed system provides various informational supports to the users via the human-following robot. For example, Augmented Reality (AR) is as an application of the proposed system. Generally, positions and orientations of a user camera are needed for AR system. In the proposed system, the human-following robot built local maps around the users while following them. Then, camera position estimation using maps is achieved for AR without using markers. This paper calls the proposed system with map building and informational supports to users 'Mobile Intelligent Space'. At first, map building while human following is introduced. Especially, some methods to assure reasonable map building speed and stability simultaneously in wide area are described. Experiment results are also shown in this paper.