PURPOSE: To repair or exchange a part or parts to generate a fault by measuring the tendency of degrading facilities, grasping the degrading tendency before the facilities break down and raising an alarm.

CONSTITUTION: Sensors 3 are mounted at equipments 2 in the facilities of respec tive buildings so as to always measure energy consumption, temperature, vibra tion, flow rate, pressure, sound or distortion. The analog data measured by the sensors 3 are transmitted through data transmission lines 4 to a monitoring device 1. A fluctuation value calculation part 6-3 receives operation record data from an operation record file 7 by operating a file access part 6-2, checks whether the operation record data is within the range of an allowable value set in advance or not, and dispatches the data while adding an alarm signal as needed. Thus, the degradation tendency for a lot of equipments can be totally grasped at one spot and man-hour for the patrol of a maintenance staff can be saved.