A unit for constructing a robot with units, wherein a joint unit comprises joint
means and is organized in a joint casing having a surface profile of a dice-like
cube, or a uniaxial cylindrical body, or an orthogonal dual-axis cylinder-like
cubic with a uniform joint means separation distance. The joint means comprises
N positioning projections disposed about the center axis thereof at equal intervals
and equal angles and N connecting screw holes respectively disposed at positions
rotated from these projections by 360/2N about the center axis thereof. Also,
a zero-degree joint power transmission unit converts and transmits the rotations
of the joint unit rotated, by itself, relative to an input joint fixed shaft fixed
to the joint casing, to the rotations of an output rotating shaft disposed a joint
unit separation distance away thereform.