PURPOSE: To improve the centering accuracy of a chip part by dividing a cam into a part including the rolling surface of a cam follower and a part fixed to a cam shaft to be adjusted and assembled, and fixing the position of the descent end of a nozzle at a centering station.

CONSTITUTION: A boss portion 6 of a cam is bound to a cam shaft 5 in the rotating direction by a key 7, and fixed by a set vis. A cam plate portion 10 including a rolling surface 9 of the cam is fixed to the boss portion 6 of the cam by a bolt. At the time of fixing the cam plate portion 10 to the boss portion, at a portion where even if the cam shaft 5 is rotated, the lift amount of the rolling surface 9 of the cam will not change, it is fixed in such a manner that the rolling surface 9 is concentric with the center of rotation. In the thus adjusted and assembled cam, a cam follower 12 moves in the same manner as shown in the timing chart of the cam and the motion is transferred to a nozzle driving lever 13.