To prevent the switching time influences power saving efficiency and packet loss prevention performance, it is provided a network apparatus for transferring packets, including a transfer part for transferring received packets to a given destination, and a determining part for obtaining traffic volume of the packets to be transferred. The determining part determines periodicity of changes to the traffic volume, predicts traffic volume after a predetermined period of time with use of the determined periodicity, and controls transfer performance of the transfer part based on a result of the traffic volume prediction.