The invention relates to a rocker arm including a roller, a pair of side walls for supporting the roller, a pivot engaging portion and a valve engaging portion, in which the configuration of the valve engaging portion, and the relative position of the roller, the pivot engaging portion, and the valve engaging portion are set with high accuracy. In the rocker arm, the roller, while being in contact with a cam, is rotatably provided between a pair of side walls forming a rocker arm body. The rocker arm body is of a two-piece structure including a first piece which includes: the pair of side walls adapted to support the roller; and a valve-engaging portion through which, as viewed longitudinally of the rocker arm body, first end portions of the side walls merge with each other; and a second piece which is a pivot engaging member fixedly secured to the remaining second end portions of the side walls.