The active rule system is a key element of the rule-based mobile agent middleware system for activeness and autonomy of the sensor network. The rule manager, which is the main components of active rule based mobile agent framework and active rule system, performs the control and management of the rule-related processes. In this paper, we design and implement the roles and functions of the rule manager in detail. The proposed rule manager plays an important role in the sensor network environment. The sensor data server loads the active rule on the mobile agent by Authors Yon Sik Lee received the B.S. and M.S. degrees in Computer Science from