PURPOSE: To modify fault decision algorithm on the basis of a past alarm generation frequency and send out an alarm speedily as to the alarm monitor system which monitors a fault of a system having various packages(PKG) to be monitored.

CONSTITUTION: This system is provided with an information editing circuit 1 which outputs alarm data of specific gathering cycles up to now as alarm generation management data, and an input/output memory 2 which holds alarm generation frequency data 5 corresponding to the past alarm sending frequency and the alarm generation management data 6 outputted by the information editing circuit 1. The system is equipped with a sending decision means 7 which decides whether or not an alarm based upon current alarm data is sent out by referring to the alarm generation frequency data 5 in the input/output memory 2, sends out the alarm in a shorter alarm generation continuation time as the alarm generation frequency is larger, and updates alarm sending frequency data 6 on the corresponding item in the input/output memory 2 in response to the sending of the alarm.