A part of the elements discovered in a network are chosen to be monitored, and a user such as a network administrator is allowed to appropriately monitor desired elements. A network management server collects information on elements in the network, and displays collected information on a GUI screen. The user is allowed to choose an element based on the information displayed on the screen, and the element chosen by the user is then registered as an object to be monitored. Information is collected including elements which are not registered, and displayed on the screen along with a result of comparison to the registered elements.