A robot system includes an arm with a plurality of joints, the arm being configured to assume a first position and a second position, an end effector attached to the arm, the end effector having a specific position, and a force detector configured to detect a force or a torque applied to or generated by the arm or the end effector, and a robot control apparatus configured to receive an output value from the force detector to change the arm from the first position to the second position while the end effector remains in the specific position, and store the second position of the arm in a memory so as to relate the second position of the arm with the specific position of the end effector.