Robotic manipulators are increasingly deployed in complex environments or to perform complex tasks. Studies on dual-arm-robots have been continually carried out in robotics areas to provide robots in dangerous environments, similar to those which human beings would be normally in, without a special change to the working environment. In previous study, a dual-arm-robot has been designed. The robot, however, has some defects in its heavy weight and big shape. In order to reduce weight of an arm robot, the robot has been designed using a hollow-shaft-servo- assembly. The hollow-shaft-servo-assembly is composed of a hollow-shaft-servo-motor, a hollow- shaft-harmonic-drive, a hollow-shaft-brake, a hollow-shaft-encoder, and a servo-drive.