This paper presents the social behavior of a physical agent in intelligent space. Intelligent Space (iSpace) is a space in which many intelligent devices, called distributed intelligent network devices (DINDs) and including not only sensors but also actuators, are installed. Robotic devices, which provide services to users, are considered as physical agents in iSpace. For facilitating long-term communication between users and a robot, we focus on building a social relationship between a user and a robot. Toward this end, a methodology for designing social behaviors of the robot is required. Therefore, we have used an ethologically inspired approach to construct a robot behavioral model for an iSpace-based elderly monitoring support system. In this paper, the robot behavioral model is presented and implementation of robot behaviors is discussed.