This paper describes the technique for detecting an abnormal vibration of the rolling bearing of a practical rotating machinery. The rolling bearing is diagnosed from time domain vibration data measured by an accelerometer, and spectrum data obtained by the frequency analysis. Two diagnostic methods are proposed. One is the case that vibration data can be obtained from the normal rolling bearing. The other is the case that vibration data cannot be obtained from the normal rolling bearing. Then, the effectiveness of the diagnosis system was verified for the rolling bearing with defective ball, outer race and inner race.