Precise detecting instrument for bearing ring

A precise detecting instrument for a bearing ring comprises a five-pass joint, five measuring bars and a dial indicator. Five ports of the five-pass joint are in screw connection with the five measuring bars respectively, and the five measuring bars comprise a first measuring bar, a second measuring bar, a third measuring bar, a fourth measuring bar and a fifth measuring bar respectively. The dial indicator is fixed on the first measuring bar through a fastener. A support component is fixed on the second measuring bar through a fastener. The support component comprises a support and a measuring bearing bar which is arranged in a groove of the support, and the support and the measuring bearing bar are located through a nut arranged in a kidney-shaped hole. A support component is fixed on the third measuring bar through a fastener. A fastener is fixed on the fourth measuring bar. By means of the precise detecting instrument, the defect of the incapability to guarantee that the whole section plane is measured pr