A circuit breaker comprising: circuit breaking unit including a fixed contact and a movable contact whose contact points are in contact with each other; and an energy-accumulating unit for accumulating energy of a closing spring for controlling the contact between the fixed contact and the movable contact, wherein the energy-accumulating unit includes: a main energy-accumulating unit including a cam shaft, a main output gear disposed on the cam shaft, and a main energy-accumulating casing for accommodating the main output gear; and an auxiliary energy-accumulating unit including an electromotive energy-accumulating unit linked with the cam shaft, and a manual energy-accumulating unit linked with the electromotive energy-accumulating unit, wherein bevel gears inside the manual energy-accumulating unit are engaged with each other by an external force to transmit the input external force to the electromotive energy-accumulating unit to accumulate the energy of the closing spring; wherein the bevel gears comprise a primary bevel gear and a secondary bevel gear, characterised in that the primary bevel gear and the secondary bevel gear are arranged to be spaced apart from each other when the manual energy-accumulating unit is not in operation, and wherein the primary bevel gear and the secondary bevel gear are arranged to be engaged with each other when the manual energy-accumulating unit is in operation. circuit breaking unit including a fixed contact and a movable contact whose contact points are in contact with each other; and an energy-accumulating unit for accumulating energy of a closing spring for controlling the contact between the fixed contact and the movable contact, wherein the energy-accumulating unit includes: a main energy-accumulating unit including a cam shaft, a main output gear disposed on the cam shaft, and a main energy-accumulating casing for accommodating the main output gear; and an auxiliary energy-accumulating unit including an electromotive energy-accumulating unit linked with the cam shaft, and a manual energy-accumulating unit linked with the electromotive energy-accumulating unit, wherein bevel gears inside the manual energy-accumulating unit are engaged with each other by an external force to transmit the input external force to the electromotive energy-accumulating unit to accumulate the energy of the closing spring; wherein the bevel gears comprise a primary bevel gear and a secondary bevel gear, characterised in that the primary bevel gear and the secondary bevel gear are arranged to be spaced apart from each other when the manual energy-accumulating unit is not in operation, and wherein the primary bevel gear and the secondary bevel gear are arranged to be engaged with each other when the manual energy-accumulating unit is in operation. a main energy-accumulating unit including a cam shaft, a main output gear disposed on the cam shaft, and a main energy-accumulating casing for accommodating the main output gear; and an auxiliary energy-accumulating unit including an electromotive energy-accumulating unit linked with the cam shaft, and a manual energy-accumulating unit linked with the electromotive energy-accumulating unit, wherein bevel gears inside the manual energy-accumulating unit are engaged with each other by an external force to transmit the input external force to the electromotive energy-accumulating unit to accumulate the energy of the closing spring; wherein the bevel gears comprise a primary bevel gear and a secondary bevel gear, characterised in that the primary bevel gear and the secondary bevel gear are arranged to be spaced apart from each other when the manual energy-accumulating unit is not in operation, and wherein the primary bevel gear and the secondary bevel gear are arranged to be engaged with each other when the manual energy-accumulating unit is in operation.