A mobile robot with a diagram indicating a moving path of a subject and a diagram showing a connection between locations, is capable of generating a path on which a subject is predicted to move from information of the subject detected by a detector, a detecting direction of the detector along the path, or tracking the subject by tracing the path, and predicting a location of a destination of the subject even when the subject has moved to another location. Further, the robot is capable of determining an abnormality based on detected location of the subject.