Cam and its manufacturing method

A thick plate-shaped metal material B to be worked is pressed by a punch 10 and a plate pressing member 11, received by a die 12 and a backward pressing member 13, and pressed, thereby shearing its outline into an arc-cam shape. Upon shearing, when the material B is pressed by the punch 10 and backward pressing member 13, a cylindrical convex portion 16a is formed on one plate surface of the extending portion 16 in accordance with a concave 10a of the punch 10, the other plate surface is punched by a projection 13b of the backward pressing member 13 to thereby form a shaft through-hole 17, and a concave portion 16b is also formed on the back side of the material B corresponding to the convex portion 16a by a projection 13a. Unevenness of the thickness in the direction in the direction of an edge position 16c of the extending portion 16 is prevented. Upon punching of the cam, the occurrence of cut break surfaces on a punched cut surface is suppressed, deterioration in bore precision of the shaft through-hole is prevented, and a deviation of the position of contact with a follower is eliminated, thereby improving operational precision.