In order to operate the relative posture between a work (4) gripped by a robot (1) and an arbitrary work point (A) without changing the position of a certain point (P), the work point (A) is defined on the reference coordinates of the robot (1) and when the work (4) gripped by the robot (1) is subjected to a teaching operation with respect to the work point (A), the work point (A) is temporarily controlled as if it were the end effector of a robot control point (R). As the work (4) is rotated around the work point (A), the posture of the work (4) is changed to a desired relative posture with respect to the work point (A). In this manner, the posture of the work (4) gripped by the robot can be changed to a desired relative posture within a short period with respect to the work point (A) and the teaching time can be reduced.