PURPOSE: To form easily a cam in a short time, and to reduce the cost of manufacturing by superposing plural pieces of thin plate-shaped cam forming plates, and inserting ad sticking a connecting member to a connecting hole.

CONSTITUTION: A cam forming plate 1 is formed by cutting an original plate A by laser and forming the whole to a roughly egg-shaped form, also through- providing a shaft hole 3, and also through-providing plural connecting holes 5... along the side of an outside peripheral surface 4. At the same time, a key groove 6 is formed in the shaft hole 3 by laser cutting, and also fitting holes 7, 7 and 7 are also formed along the periphery of the shaft hole 3. Subsequently, plural cam forming plates 1 are supposed, a connecting member 8 is inserted into the connecting holes 5..., respectively, and caulked, the forming plates 1... are made a closely adhering state, and a desired thick cam 9 is formed. This cam 9 is attached to a cam shaft 10, the cam shaft 10 is inserted into a boss 13 to which the cam 9 has been fixed, and the boss 13 and the cam shaft 10 are fixed with a screw 18.