1. A portable terminal apparatus comprising: a first communication unit which is configured to connect to a server on a network and performs data transmission; a second communication unit which is configured to connect said portable terminal apparatus to a communication apparatus external to the portable terminal apparatus using a wireless local area network (LAN), and which is configured to perform data transmission; a temporary storage unit which, using said first communication unit and said second communication unit at the time of relaying a communication of data between said server and said communication apparatus, is configured to temporarily store said data; and a control unit which is configured to control said data communication of said first communication unit and said second communication unit asynchronously and in parallel at the time of relaying the communication of data between said server and said communication apparatus, wherein said control unit is configured to terminate said communication, and to configure said communication by one session between said server and said portable terminal apparatus and another session between said portable terminal apparatus and said communication apparatus.