PURPOSE: To provide the plant equipment monitor device which can detect abnormality of the equipment by grasping minute variation of a detection signal.

CONSTITUTION: The plant equipment monitor device which detects the abnormality of the monitor equipment by decentralizing and arranging plural sensors 1, 2, and 16-18 in monitor areas is equipped with an acoustic information input means and an image information input means 20 which calculate abnormality conviction degree from detected values obtained through the sensors 1, 2, and 16-18, a judgement part 21 which judges whether or not abnormality detection needs to be performed again on the basis of the abnormality conviction degree, a detection condition storage part 22 which judges whether or not parameters for signal processing at normal time and redetection processing are required, and a detection control part 24 which places signal processing parts 19 and 20 in operation so as to perform detection normally in detection order set in the detection condition storage part 22 and performs control so as to perform signal processing on the basis of the parameters for detection processing for redetection processing set in the detection condition storage part 22 when the judgement part 21 requests the redetection, so minute variation of the detection signal due to abnormality which is hidden behind a disturbance component and overlooked before with high possibility can be detected with high precision.