PURPOSE: To easily prepare an Oldham's coupling by forming the opposite parts in the direction of diameter of a ring-plate member into projection bodies through press work and joining said ring-plate members so that the projection bodies are directed oppositely each other and shifted by 90°.

CONSTITUTION: In order to prepare the captioned Oldham's coupling, the opposite parts in the direction of diameter of a ring-plate member 3a are formed into projection bodies 3b in U-form through press work. Two ring-plate members are superposed so that the projection bodies are directed in the opposite directions each other and the positions are shifted by 90°, and the proper positions on the ring-plate members are joined through spot welding. Therefore, an Oldham's coupling can be prepared from one kind of ring-plate member through simple machining, and cost cut is enabled because of mass production effect.