PURPOSE: To easily perform the calibration work in a short time by holding an auxiliary pole with a holding hand fitted to the tip of an arm, and setting the tip of the auxiliary pole at the predetermined reference point so as to perform the calibration of a coordinate system.

CONSTITUTION: A holding hand 3 is fitted to a tip of an arm of a robot 2. In this condition, an auxiliary pole 10 is held by the holding hand 3, and a relative position of a tip of the arm and a tip of the auxiliary pole 10 is made to coincide with a relative position of a tip of the arm and a tip of a pole for calibration. Continuously, a tip of the auxiliary pole 10 is set at the predetermined reference point so as to perform the calibration of a coordinate system. Since the auxiliary pole is held by the holding hand, calibration of the coordinate system can be easily performed in a short time without requiring the exchanging work of the holding hand and the calibration pole.