Abstract: A business process system for transmitting and receiving various pieces of business data by connecting an indefinitely large number of enterprises through a network includes a client terminal possessed by an order source connected to an open network layer, equipped with an application for realizing a peer-to-peer network architecture, and serving as a member participating in the peer-to-peer network, an order reception database connected to a network layer inside an order reception base as a segment isolated from the open network layer, equipped with the application, connecting to the client terminal by a peer-to-peer connection upon execution of the application by the client terminal, recording data sent from the client terminal, and reading data to be sent out of the recorded data, and a node connected to an intermediate network layer at the order reception base serving as a segment isolated from the open network layer and from the inside network layer, collecting and temporally maintaining the data sent fr