Four steps are required to demonstrate mirror image cognition using a robot. These steps are: 1) the robot imitates the action of its own image reflected in a mirror, 2) the robot imitates an action taken intentionally by another robot as imitative behavior, 3) the third one is conducted in an environment where the other robot is controlled completely via cables from the self-robot to imitate the behaviour, and 4) the robot imitates the random actions of another robot. In the 1st step, it is a fact that the mirror image of the robot is the same action as the robot itself performs, however, it is possible that the mirror image could be another individual intentionally performing an action in the same manner as oneself, or it could be another performing the same action as oneself by coincidence. However, these possibilities can be eliminated by discriminating the 1st step from the other steps using a given evaluation method.