1. A network-management device comprising: an acquiring unit that acquires device information on all network devices operating on a network; a first storing unit that stores therein the device information; a display unit that displays the device information in a list; a designating unit that designates a layout position on a map where device information on each of the network devices is to be laid out; a selecting unit that selects a display image for each of the network devices based on type of the network device; a creating unit that creates the map by laying out on the map the device information on each of the network devices with the display image based on the layout position; a specifying unit that specifies a creation state of the map; and a second storing unit that stores therein the creation state in association with the map.