PURPOSE: To permit the indexing with high accuracy by supporting a turntable under a static pressure onto a fixed board and conneting said turntable onto a driving shaft through a flexible coupling and preventing the transmission of the vibration of a breading for supporting the driving shaft, onto the turntable.

CONSTITUTION: A turntable 2 is supported under a static pressure in the thrust and radial directions onto a fixed board 1 by a bearing member 3. Said turntable 2 is connected through a flexible coupling 6 to the upper edge of a driving shaft 4 rotatably supported through a bearing 5 onto the fixed board 1. A revolution detector 7 is fixed onto the fixed board 1 so as to be arranged on the revolution center line of the turntable 2, and the input shaft 8 of the revolution detector 7 and the turntable 2 are conneected through a center connecting shaft 9 which is rotatably inserted into the center of the driving shaft 4 and a flexible coupling 10. Therefore, the transmission of the vibration of the bearing 5 and the force by the driving apparatus onto the turntable 2 is prevented, and the indexing with high accuracy is permitted.