PURPOSE: To stop stably the rotation of a shaft to both roller support wall parts without using an antirotation member in a rocker arm provided on a cylinder head to receive the sliding operation by a cam for opening and closing a valve.

CONSTITUTION: On the outside opening end edge of a shaft inserting hole provided in a pair of roller support wall parts 7 of a rocker arm body a tapered chamfer 15 is provided continuously in the circumferential direction. Two chamfer widths opposed 180° to the circle in the chamfer 15 are set larger than those of other chamfered parts. Thus, the two spots opposed 180° to each other have projections 17a shaped to corresponding to the wide width part 15a of the chamfer 15 in parts 17 plastically deformed by calking of the shaft 13, so that the shaft 13 is prevented from rotating by the projection 17a hooked on the wide width part 15a of the chamfer 15.