Abstract: The present invention relates to an automatic control device for a padlock which enables automatic control of the padlock connected to a circuit breaker installed in a distribution board of semiconductor or LCD equipment. In the present invention, a pair of cylinders, which can supply and cut off electric power to and from a load terminal, is directly installed on top of the circuit breaker installed in the distribution board, so that a switch of the circuit breaker is turned on/off as the pair of cylinders selectively operates according to an external control signal. As a result, it is unnecessary to separately install the padlock for switching on/off the circuit breaker.