A device that performs a master/slave switching process dynamically changing a device functioning as a master device in a network in consideration of fixed device performances and also variable device states is provided. A device's own device information managing section (15) of a master device (1) manages device's own device information regarding its own device. Another device information managing section (16) manages other device information regarding other devices, which are slave devices. A schedule information managing section (17) manages schedule information regarding master device candidates. A device information processing section (13) obtains predetermined information, such as the remaining amount of battery, from a slave device specified based on the other device information and the schedule information at a predetermined time. The device information processing section (13) then compares the obtained predetermined information and the device's own device information to determine whether a device more suitable as the master device than its own device (1) is present. If such a suitable device is present, a master/slave switching process is performed with this suitable device.