Wireless terminal device and control method thereof

A wireless terminal device (1) for use in a store-and-forward type wireless network includes a wireless communication unit (11), a memory (12), and a control unit (13). The memory (12) is coupled to the wireless communication unit (11) and is configured to store messages transferred via the wireless network. The control unit (13) is configured to adjust, based on first information, at least one of a maximum number and maximum retention time of messages stored in the memory (12). The first information relates to a degree of contribution of the wireless terminal device (1) to success in sending messages from a source node to a destination node via the wireless network. It is thus possible to provide, for example, an efficient memory control method suitable for a store-and-forward type wireless network.