PURPOSE: To improve the accuracy in diagnosys of the abnormal vibration of the rotary machine, by inputting the matrix expression of the kinds and the indication of abnormality at the time of initial setting, and weighting each indication based on the analysis of the measured signal.

CONSTITUTION: The initial setting of the matrix expression of the kinds and indication of the abnormality (indication matrix), is a reference value of each signal, and the like performed. Shaft vibrations and various other signals are inputted, frequency analysis and the conversion to a physical quantity are performed, and the abnormality is judged. When the abnormality is judged, the computation of the weighted total point is performed by using the point matrix. The name of the abnormal kind is displayed on a CRT only when the reference point is exceeded. When the result of the point computation for each abnormal kind is 90 or more, it is judged that the abnormality has occurred, and the point is displayed on the CRT together with a symbol. When the points of a plurality of abnormalities become 90 or more, the points are sequentially displayed. If the abnormality kinds of the points 70 or more are present, the names and the points are sequentially displayed. Therefore the accuracy in the diagnosis is improved.