The invention provides an operating mechanism of a circuit breaker. The operating mechanism of the circuit breaker comprises a mounting bracket, a driving shaft, a cam assembly and an energy storage assembly. The driving shaft is rotationally mounted on the two side plates of the mounting bracket. The cam assembly is rotatably mounted on the driving shaft and is located within the mounting bracket. The operating mechanism further comprises an indication device matched with the cam assembly. The indication device is used for the in-place state of the energy storage of the energy storage assembly. The indication device comprises a guide rod and a micro-switch, wherein the guide rod and the micro-switch are connected. The guide rod is in contact connection with the cam assembly. The driving shaft drives the cam assembly to rotate, so that the cam assembly pushes the energy storage assembly to store the energy. When the energy storage of the energy storage assembly is in the in-place state, the cam assembly drives the guide rod to swing and trigger the contact of the micro-switch. According to the technical scheme of the operating mechanism of the circuit breaker, the guide rod is in linkage with the cam assembly when the energy storage of the energy storage assembly is in the in-place state, so that the contact of the micro-switch is triggered. Therefore, the operating mechanism of the circuit breaker is directly indicated to be just in place. The indication device is simple in structure and explicit in indicating effect. By the indication device, an operator can conveniently and rapidly judge whether the energy storage of the energy storage assembly is ready or not.