A robot control device comprises a mass parameter setting unit which sets a mass parameter, and a stop command unit which sends a stop command of a robot. A first upper limit value regarding external force and a second upper limit value smaller than the first upper limit value have been set. The stop command unit stops the robot when estimated external force exceeds the first upper limit value. Furthermore, the stop command unit makes the robot to be in a stop state when an average value of the external force exceeds the second upper limit value.