PURPOSE: To provide a structure of the tool holding equipment of the robot which can change smoothly a distance between a tool and a workpiece.

CONSTITUTION: A holding part 22 and a sanding machine 6 are supported by means of the links 4 and 5 arranged rotatably to a frame 3. A spring 7 and the movable part of an air cylinder 8 are connected to one end of the link 4 by means of a shaft 15. Another end of the spring 7 and the fixing part of the air cylinder 8 are fixed to the shaft 31 arranged to the frame 3. The tension of this spring 7 cancels the weight of the sanding machine 6 and the holding part 22.