To improve the durability of a parking mechanism by pressing a bearing into a bearing hole without slanting easily, preventing the wear of the bearing and the bearing hole and the generation of a burr and turning a cam shaft smoothly.

A bearing 15 is formed by rounding an elastic sheet material in a cylindrical shape with a larger diameter than that of a bearing hole 9. A guide hole 9c with such bigness that the bearing 15 in a free state can be stored is formed between the bearing hole 9 and the boot groove 9a. The bearing 15 in the free state is stored to the through hole 22b of a guide table 22 while projecting its tip 15c. A stopper pin 21 is inserted in the insertion hole 22c of the guide table 22 and the tip of the bearing projected from the through hole 22b is inserted into the guide hole 9c while making the stopper pin 21 to a fulcrum and the other end 15d of the bearing 15 is push-pressed by a press-in tool 23 and the bearing 15 is pressed into the bearing hole 9.