A planning means generates a plan to be executed by agents on a node. In the case where the plan generated uses an uncertain knowledge required to be processed in other nodes, a judging means judges the communication line connecting the node and a network is low or high in reliability. In the case where the reliability of the communication line is low, an agent management unit moves the agent for executing the plan to another node for processing the uncertain knowledge. In the case where the reliability of the communication line is high, on the other hand, a cooperation protocol realization means requests an agent on another node to process the uncertain knowledge. An agent execution means executes the plan generated.