1. A manual-mode operating system for a robot provided with an end-effector, comprising: a display section including a screen for displaying an image of an end-effector; a first input section for an input of coordinate system data on said screen of said display section, displaying said image of said end-effector, said coordinate system data designating a manual-mode coordinate system used for describing an orientation of said end-effector; a coordinate system setting section for setting said manual-mode coordinate system at a spatial position corresponding to an input position on said screen of said display section, based on said coordinate system data input through said first input section; a second input section for an input of orientation data using said manual-mode coordinate system set through said coordinate system setting section, said orientation data instructing said orientation of said end-effector; and an orientation adjusting section for adjusting said orientation of said end-effector, based on said orientation data input through said second input section.