This paper shows vibration characteristics of a sliding bearings. Especially, we study self-excited vibration (Oil whirl) of the sliding bearings. We tried three analysis methods, which are trajectory of shaft vibration and tracking analysis, and particle number of wear debris in lubricant generated by direct contact between a shaft and outer race of the sliding bearing. In a sliding bearing, an oil whirl, which is a characteristic self-oscillation, occurs at a rotation speed less than twice the critical speed of the experiment system. In addition, since the vibration of the foundation affects the vibration of the slide bearing when installed on a base with low rigidity, it is necessary to install it on the one with high rigidity. It seems that the bearing inner ring and the outer ring did not contact in the runout due to the natural frequency of the experiment system. The oil whirl contacted and the increase of wear debris in lubricant generated by the direct contact was confirmed.