This section of the book describes the mechanical design of humanoid robots which are human-like robots with human-like features such as a head, two arms, and two legs. To design such humanoid robot, we have to realize required functions with compact design. In this section, some mechanical components and the full-body design examples are presented. After discussing the historical perspectives in Sect. 1, I briefly describe the design of each mechanical component, i.e., the leg/foot, multi-fingered hand, and face mechanisms. Lastly, I briefly describe an example full-body design.