A motion sensing device with a vacuum circuit breaker (A), wherein the vacuum circuit breaker (A) includes: a push rod assembly including a push rod movable upwardly or downwardly to insert or withdrawn a vacuum interrupter ; and a main shaft having one end pivotably coupled to the mechanism assembly and the other end coupled to an end of the push rod, wherein the main shaft transmits power generated from the mechanism assembly to the push rod , wherein the motion sensing device comprises: a sensor module installed adjacent to the main shaft for sensing a motion state of the main shaft ; characterized by a bracket coupled to the sensor module and supporting the sensor module , wherein the sensor module includes: a circuit facing toward the main shaft ; and a light-emitter and a light-receiver disposed on the circuit and side by side, wherein the light-emitter and the light-receiver face toward the main shaft , wherein light emitting from the light-emitter is reflected from a plate plane of the main shaft , and the light-receiver receives the reflected light, wherein the bracket (ODO) is disposed on one side face of the main shaft . a push rod assembly including a push rod movable upwardly or downwardly to insert or withdrawn a vacuum interrupter ; and a main shaft having one end pivotably coupled to the mechanism assembly and the other end coupled to an end of the push rod, wherein the main shaft transmits power generated from the mechanism assembly to the push rod , wherein the motion sensing device comprises: a sensor module installed adjacent to the main shaft for sensing a motion state of the main shaft ; characterized by a bracket coupled to the sensor module and supporting the sensor module , wherein the sensor module includes: a circuit facing toward the main shaft ; and a light-emitter and a light-receiver disposed on the circuit and side by side, wherein the light-emitter and the light-receiver face toward the main shaft , wherein light emitting from the light-emitter is reflected from a plate plane of the main shaft , and the light-receiver receives the reflected light, wherein the bracket (ODO) is disposed on one side face of the main shaft . a sensor module installed adjacent to the main shaft for sensing a motion state of the main shaft ; characterized by a bracket coupled to the sensor module and supporting the sensor module , wherein the sensor module includes: a circuit facing toward the main shaft ; and a light-emitter and a light-receiver disposed on the circuit and side by side, wherein the light-emitter and the light-receiver face toward the main shaft , wherein light emitting from the light-emitter is reflected from a plate plane of the main shaft , and the light-receiver receives the reflected light, wherein the bracket (ODO) is disposed on one side face of the main shaft . a circuit facing toward the main shaft ; and a light-emitter and a light-receiver disposed on the circuit and side by side, wherein the light-emitter and the light-receiver face toward the main shaft , wherein light emitting from the light-emitter is reflected from a plate plane of the main shaft , and the light-receiver receives the reflected light, wherein the bracket (ODO) is disposed on one side face of the main shaft . <EOS>