To sufficiently demonstrate a vibration isolation effect by detecting the storage amount of a displacement angle generated between the drive side of a shaft joint and a load side and correcting the displacement angle of the load side to the drive side of the shaft joint based on the storage amount.

By signals from a saddle type photosensor 90 inputted to a displacement amount detection part 100 at the point of time of being rotated and stabilized (5 rotations), synchronizing signals 103 are measured. Simultaneously, by the signals from the saddle type photosensor 91, the measurement of the synchronizing signals is stopped. The pulse number of the synchronizing signals 103 measured during the time is stored and the stored pulse number 106 is inputted to a displacement amount synthesis part 107, added to a normal rotation drive pulse 101 and turned to the normal rotation drive pulse 101A. That is, the stored pulse number 106 is added at the time of elevating an elevating and lowering block and subtraction is performed at the time of lowering the elevating and lowering block. By the constitution, for instance, even when the displacement angle by a smoothing device to the pulsation of the shaft joint 1 is generated, it is detected and corrected.