PURPOSE: To execute detailed state supervision for a network by collecting management information such as a communication control parameter, a commu nication load and a communication state from plural work stations and network equipments connecting to a local area network and executing a rule including a simple program for network state supervision described by the user.

CONSTITUTION: A rule execution means 13 applies a rule for a network state supervision inputted from a rule description file 4 and translated to a network component in response to an application condition inputted from an application condition description file 5. The management information collected through a management information collection means 3 is processed according to the rule by the rule execution means 13 to generate warning and log. Thus, the complicated state of the network is detected and the detailed state of the network is supervised.