When a management operation for changing an IP address of a device is applied to a plurality of devices, and the devices as operation targets include a network device management apparatus, the self apparatus is put to the end of operations, and the IP address change operation is applied to other devices (1808). As a result, even when the network device management apparatus as an operation target device is rebooted, since the management operations for all devices as operation targets are complete so far, a situation that the management operations for other devices are not executed due to an interruption of processing by rebooting can be avoided.