The positional relationship between a master terminal and a slave terminal and the positional relationship of the slave terminal with the master terminal and with other slave terminals are measured, and a slave terminal subject to switching to master terminal is selected using the positional relationship. A network is then reconstructed with the slave terminal subject to switching selected in this manner as the new master terminal, and as a result the terminals forming the network prior to switching are prevented from falling outside of the communication range of the new master terminal and short range radio communication is maintained with the same terminals as those prior to switching.