To simplify production, a hollow-structure robot link-constituting member is obtained by joining two or more formed members obtained by press-forming steel sheets. Compared to when the robot link-constituting member is formed of castings, the thickness can be easily reduced and high strength can be maintained by forming a hollow structure by joining at least two formed members obtained by press-forming steel sheets. In this manner, significant weight reduction can be achieved compared to iron castings, and occurrence of defects can be reduced compared to aluminum alloy castings.