A client terminal comprises a first application unit which transmits and receives data to and from a server, and a second application unit which transmits and receives data to and from the first application unit. An instruction transmitting unit in the second application unit transmits a user's instruction to the first application unit, and a state holding and transmitting unit transmits state information of the second application unit to the first application unit. A request generation unit in the first application unit generates a request command for the server based on the instruction received from the instruction transmitting unit, a state addition unit adds the state information received from the state holding and transmitting unit to the request command, and a request transmitting unit transmits the request command to which the state information is added to the server.