Robot teaching system

A robot teaching system comprising:

• a first end effector having a gripping structure and used for teaching;
• a second end effector having the gripping structure and mounted on a robot;
• a position/posture fixing tool having a gripped structure in which a position and a posture with respect to the first end effector and the second end effector are uniquely determined by being gripped by the gripping structure of the first end effector and the second end effector;
• a teaching data transformation unit configured to transform first teaching data representing position/posture information of the first end effector during a teaching operation into second teaching data representing position/posture information of the second end effector;
• and
• a robot control unit configured to cause the robot to operate based on the second teaching data,
• wherein the teaching data transformation unit transforms the first teaching data into the second teaching data using
• a first relative position/posture indicating a relative position/posture between the first end effector and the position/posture fixing tool when the position/posture fixing tool is gripped, and
• a second relative position/posture indicating a relative position/posture between the second end effector and the position/posture fixing tool when the position/posture fixing tool is gripped.