To manufacture the body part of a rocker arm by press working.

The body part 11 of the rocker arm 6 is manufactured by bending a metallic sheet material upward by press working. A member for positioning relative to a valve stem is manufactured separately from the body part 11 by processing a sheet metal or bending a wire material to be quickly fitted to a valve contact part 10 by a spring force and form a pair of positioning parts to hold the upper end of the valve stem in the lateral direction.