A network system including a plurality of devices connected to one another via a network includes a grouping processing section configured to, from among the plurality of devices, perform grouping of devices having at least one predetermined item common thereto in terms of device usage, and a representative selection section configured to select one of the devices having been grouped as a representative device. Further, the network system includes a control section configured to cause non-representative devices, which are remaining devices resulting from excluding the representative device from the devices having been grouped, to perform synchronously a mode switching operation for switching between a normal mode and a power saving mode in which an amount of power consumption is smaller than that in the normal mode, and cause the representative device to perform the mode switching operation independently of the mode switching operation performed by the non-representative devices.