NETWORK MANAGEMENT SYSTEM

PROBLEM TO BE SOLVED: To provide the network management system that can specify a problem effectively with a small use amount of memory capacity. SOLUTION: A fault management section 34 that estimates a cause to a fault in the network management system includes a fault counter 54 that is provided corresponding to each fault event caused in each device and a count comparator 52 that estimates a fault cause to the fault event by a prescribed method based on contents of the fault counter 54. The fault counter 54 includes plural storage areas to store each count, a means that sets an upper limit capacity to each storage area based on a propagation model, and a logic to update contents of the storage area corresponding to a received fault event based on a configuration management information schemer definition, a propagation model, configuration information and prescribed rules for update in response to the received fault event.