To provide a method of manufacturing a cam lobe at a low cost by further reducing the weight of the cam lobe while dispensing with conventionally required broaching of the inner peripheral surface of a shaft hole of the cam lobe in assembling the cam lobe to a camshaft of an automobile or the like, thereby dissolving a crack initiated when assembling the cam lobe to the inner peripheral surface of the shaft hole.

The hole shape 5 of the shaft hole 2 for fitting and locking the cam lobe 1 to the outer periphery of the camshaft to stop whirling in assembling the cam lobe 1 to the camshaft is formed in elliptic shape, and thin-walled parts 7 formed of recesses whose depth from a plate face 4 of a cam lobe tip part 3 is 20-25% of plate thickness 4 of the cam lobe 1, are formed on both sides of the plate face 4 of the cam lobe tip part 3. Further, a cam lobe outer peripheral surface 16 on one side of the plate face 4 of a shaft hole peripheral edge part 6 on the opposite side to the cam lobe tip part 3 with respect to the shaft hole 2 is thinned to form a thin-walled part 7 with a width reaching 48-52% of the width from the cam lobe outer peripheral surface 16 to a shaft hole inner peripheral surface 15.