PURPOSE: To provide a hydraulic rotating device in a vacuum pump, a compressor or the like capable of rotating rotors at high speed and easily made compact and kept clean without the necessity of maintenance, and also capable of decelerating or stopping the rotors at the time of synchronization slippage being generated to the rotation of the rotors without causing mechanical-electrical damage and breakdown.

CONSTITUTION: In a positive displacement vacuum pump A, plural rotary shafts 102, 103 are respectively provided with motors 106, 107 and rotating state detecting encoders 108, 109. A driving circuit rotates plural rotary shafts 102, 103 synchronously by motor current detecting parts 262, 264, a rotary shaft relative position detecting part 260 and a motor rotation command part 270. When synchronization slippage is generated, the synchronization slippage is detected, and the rotary shafts 102, 103 can be decelerated or stopped without causing mechanical-electrical damage and breakdown.