An interlocking device for a circuit breaker comprises a control assembly and an interlocking assembly which are connected with each other in a driving manner. The control assembly can be connected with a connecting rod assembly and a cam assembly of an energy storage operation mechanism of the circuit breaker in a latching manner, thereby controlling the energy storage operation mechanism to finish a switching-on/switching-off operation. A switching-off latch of the control assembly is connected with the connecting rod assembly, and a switching-on latch of the control assembly is connected with the cam assembly. A switching-on guide rod of the interlocking assembly is connected with the control assembly in a driving manner, such that the switching-on latch actuates, and a switching-off guide rod of the interlocking assembly is connected with the control assembly in a driving manner, such that the switching-off latch actuates. One end of a switching-on half-shaft is connected with the switching-on latch in a driving manner, and the other end of the switching-on half-shaft and the driving guide rod face each other. The interlocking device for the circuit breaker, which is provided by the present invention, is compact in structure, accurate in control and stable in action.