A robot system includes: a recognition means that recognizes an operator in distance image data as a security surveillance target; an area setting means that sets, in the distance image data, a common work area that a robot and the operator are allowed to enter; and a boundary setting means that sets, in the distance image data, a first boundary that the operator S is allowed to cross for entering the common work area but the robot is not allowed to cross, and a second boundary that the robot is allowed to cross for entering the common work area but the operator is not allowed to cross, wherein the crossing of the second boundary by the security surveillance target and the crossing of the first boundary by a non-target object not recognized as the security surveillance target are detected.