A mobile collaborative robot includes a force sensor which is provided on a robot support on a carriage, a robot information acquisition unit which acquires robot information including posture information of the robot main body and load information of a load acting on the robot main body, a force calculation unit which calculates the external force acting on the robot support based on the robot information, and a judgment unit which judges that the mobile collaborative robot has come into contact with a human when a difference between the external force detected by the force sensor and the external force calculated by the force calculation unit is above a predetermined value α or when a difference between the amount of change in the detected external force and the amount of change in the calculated external force is above a predetermined value α1.