In an ad hoc mode based on IEEE802.11 standard, when a wireless terminal performs a power save operation to create a network, and a network identifier identical to that of the network to be created is present, the wireless terminal does not join the network. When the wireless terminal is to join the network, and the network identifier identical to that of the network which the wireless terminal is to join is not present, the wireless terminal does not join any network. In this method, reliable connectivity can be obtained in the ad hoc mode which is not defined in the IEEE802.11 standard in detail.