A system and a process for access controlling the agent execution, based on thread history (tracing) information, in an environment in which plural agents are run simultaneously, to protect the agent environment and the agents operating in the agent environment. When an agent 130 operating on an agent environment 140 requests execution of method to be a disclosed to another agent, the agent information 123 for the agent 130 and the agent environment information on the agent environment 140 are stored in a method execution request message, by agent environment information management means 172 and by agent environment information management means 173, respectively, whilst thread visit history information 125 on the thread of the method is stored in the thread visit history management means 174. Method transmission means 180 transmits the method to an agent environment of the method requestor. The method reception means of the agent environment of the requester receives the message. Agent execution management means of the agent environment checks into execution authorization of the requested method based on the agent information and the thread visit history information with execute access control.