A robot controller and a robot control method, by which each element constituting a robot is protected. An output of a rotary encoder attached to a servomotor is read, and the motor speed is obtained by calculating the difference between a current speed and another speed in a previous speed loop. Then, a processor of the servo controller of each link of a robot arm executes a normal speed loop control in order to calculate a torque command of the motor. Next, a load torque is estimated by using the obtained torque command and the motor speed, and the estimated load torque in each speed loop is compared with a predetermined threshold. If the load torque is larger than the threshold in at least one of the axes, the robot controller judges that an abnormality has occurred in the robot, generates an alarm or warning, and then controls the robot so as to protect the element.