NETWORK MONITORING DEVICE, NETWORK MONITORING PROGRAM, AND NETWORK MONITORING METHOD

PROBLEM TO BE SOLVED: To provide a communication network monitoring device, communication network monitoring program, and communication network monitoring method for monitoring a communication network constituted by including multiple network components.SOLUTION: A monitoring system 600 includes: a monitoring control unit 51 for monitoring main alarm and related alarm to be generated based on a failure; a service interruption determination unit 57 for determining the presence/absence of interruption of a communication service on the basis of the main alarm and related alarm acquired by the monitoring control unit 51; an estimated accommodation user number calculation unit 34c for calculating the number of estimated accommodation users for each NW component; and a calender function unit 56 for calculating the number of estimated influence users on the basis of the identification information of an interruption main alarm generation network component and the number of estimated accommodation users.