To improve the practicality of a multi-agent system more by providing the translation agent device which translates a message separately from the mediating agent device which performs a mediating process between the information-provision and information-request side agent devices.

The information-provision side agent device 1 accesses a data base, etc., to provide information for the information-request side agent device 2. The information-request side agent device 2 while interactive with a user through a browser, etc., accesses the information provided by the information- provision side agent device 1. The mediating agent device 3 manages the capability information that the information-provision side agent device 1 has to perform the mediating process between the information-provision side agent device 1 and the information-request side agent device 2. The translation agent device 4 is provided separately from the mediating agent device 3 and translates the terms that the message sent and received between the agent devices.