An application cooperation system includes an instruction screen display control portion which causes a browsing portion to display a scan instruction screen, a scan control portion which stores image data output from a document reading portion, an external screen receiving portion which receives an external screen including an external control command from the external server for storage, an internal screen generating portion which generates an internal screen including an internal control command and an image data displaying area, an integrated screen generating portion which generates an integrated screen by combining the internal and external screens for output to the internal server portion, and a location information notification portion which obtains the integrated screen's network address from the internal server portion for output to the external server. The external server returns redirect information including the integrated screen's network address to the browsing portion in response to a transmission request.