To provide a flexible on-line information system reduced in load on terminal, in an on-line trade requiring instantaneity.

An agent 13 moves a network of the Internet 2 to be able to conduct desired processing by respective servers 4-11 in a center 3, by discribing a content processed in a moving destination preliminarily in a program in the agent 13 in response to requirement of a terminal 1. A processed result is read in as a data in the agent 13 to be returned to the terminal 1, and a transaction of desired information is thereby carried out in the terminal 1. For example, the agent 13 conducts, in order, such work in the each server that a customer authetication program is executed by an authetication server 6 and that buying and selling of stocks is executed by a trading server 11, when stock exchange is conducted, and returns to the terminal 1 after waiting a working result, and the terminal 1 acquires desired stock information from the agent 13 to conduct the stock exchange.