PROBLEM TO BE SOLVED: To provide a cooperation system for a large-sized signage and a tablet terminal device, in which the tablet terminal for retrieving and perusing commodities which customers are interested in, and a large-sized signage installed at a shop are cooperated, and which changes contents broadcasted by the large-sized signage dynamically in real time based on operation histories in the tablet terminal devices of a large number of customers.SOLUTION: A tablet terminal device 100 periodically collects operation histories from other tablet terminal devices 200, and prepares contents for new signage to which contents to be preferentially broadcasted are reallocated in accordance with the aggregate result of the numbers of content viewing in collected operation histories and transmits the contents to a relay device to request relay. The relay device 300 converts the contents for signage to a video signal and transmit it to a large-sized signage 400 to display it.
