A network device management unit manages a first network device, communicable with a second network device, managed by a counterpart network device management unit, in a network environment. The network device management includes a device information storage, a communication-start information, a network device management information operation unit, an available function information acquisition unit, and a display-information generator. The device information storage stores network device management information of the first network device. The communication-start information acquisition unit obtains communication-start information when the first and second network devices start to communicate. The network device management information operation unit lets the counterpart network device management unit to obtain the network device management information of the first network device. The available function information acquisition unit obtains available function information of the second network device. The display-information generator generates networked-device-function information corresponds to the obtained available function information.