A method of manufacturing a rocker arm includes blanking a piece of plate to obtain a base material for forming a rocker arm body, the base material being substantially U-shaped in plan view and having two protrusions which are substantially in parallel with each other. The base material is bent until the two protrusions are confronted substantially in parallel with each other, to provide a pair of side walls having a coupling portion between the side walls. Next, the coupling portion is curved between the side walls to provide a valve engaging portion, and the free end portions of the side walls are fixedly secured to the side walls of a pivot engaging member which is a plat plate having a semi-spherical portion formed by drawing.