PURPOSE: To make it possible to prevent abnormal wear of the slide-contact surface of a baffle key and a key way by causing an Oldham's ring to have a magnetic force and sliding the Oldham's ring in tight adherence to the baffle key by the magnetic force upon starting the operation of a machine.

CONSTITUTION: When a turning scroll 8 moves to the side of a stationary scroll 5 while making a turning movement, an Oldham's ring 9 slides by the magnetic force in a state where the Oldham's ring 9 hermetically adheres to a baffle key 11a. Hence, single hitting does not occur on the slide-contact surface of the baffle key 11a and a key way 10a. Accordingly, occurrence of abnormal wear on the slide contact surface and damage of the Oldham's ring can be prevented.