A circuit breaker, comprising a housing, a current signal collection mechanism, an operating mechanism, a contactor mechanism, cable inlet ports (103, 104), cable outlet ports (106, 107), and a control apparatus, wherein the current signal collection mechanism, the operating mechanism, and the contactor mechanism are disposed in the housing; the current signal collection mechanism comprises a first fixed contact and a second fixed contact, and the first fixed contact is electrically connected to the second fixed contact; the cable inlet ports (103, 104) are connectable to a power supply line and comprise a first electrode cable inlet port and a second electrode cable inlet port; the operating mechanism has a rotating part and a first moving contact, the first moving contact is electrically connected to the first electrode cable inlet port, and the rotating part is capable of driving the first moving contact to rotate, to make a circuit between the first moving contact and the first fixed contact connected or disconnected; the cable outlet ports (106, 107) are connectable to a power receiving line and comprise a first electrode cable outlet port and a second electrode cable outlet port, the first electrode cable outlet port is electrically connected to a second moving contact, and the second electrode cable outlet port is electrically connected to the second electrode cable inlet port; and the control apparatus is configured to control the contactor mechanism to drive the second moving contact to move, to make a circuit between the second moving contact and the second fixed contact connected or disconnected; wherein the circuit breaker further comprises a short-circuit protection mechanism, the short-circuit protection mechanism is disposed on one side of the operating mechanism, the short-circuit protection mechanism comprises an electromagnetic coil, an iron core, a shaft, an armature spring, and an armature, the electromagnetic coil is sleeved on the iron core, the armature spring is sleeved on the shaft, and the armature is fixedly connected to the armature spring; and one end of the electromagnetic coil is electrically connected to the second moving contact through a conductor, and the other end of the electromagnetic coil is electrically connected to the first electrode cable outlet port; and when a current flowing through the electromagnetic coil exceeds a preset current threshold range, electromagnetic force generated by the electromagnetic coil attracts the armature to rotate around the shaft, and the armature pushes the rotating part to rotate, so that the circuit between the first moving contact and the first fixed contact is disconnected. the current signal collection mechanism comprises a first fixed contact and a second fixed contact, and the first fixed contact is electrically connected to the second fixed contact; the cable inlet ports (103, 104) are connectable to a power supply line and comprise a first electrode cable inlet port and a second electrode cable inlet port; the operating mechanism has a rotating part and a first moving contact, the first moving contact is electrically connected to the first electrode cable inlet port, and the rotating part is capable of driving the first moving contact to rotate, to make a circuit between the first moving contact and the first fixed contact connected or disconnected; the cable outlet ports (106, 107) are connectable to a power receiving line and comprise a first electrode cable outlet port and a second electrode cable outlet port, the first electrode cable outlet port is electrically connected to a second moving contact, and the second electrode cable outlet port is electrically connected to the second electrode cable inlet port; and the control apparatus is configured to control the contactor mechanism to drive the second moving contact to move, to make a circuit between the second moving contact and the second fixed contact connected or disconnected; wherein the circuit breaker further comprises a short-circuit protection mechanism, the short-circuit protection mechanism is disposed on one side of the operating mechanism, the short-circuit protection mechanism comprises an electromagnetic coil, an iron core, a shaft, an armature spring, and an armature, the electromagnetic coil is sleeved on the iron core, the armature spring is sleeved on the shaft, and the armature is fixedly connected to the armature spring; and one end of the electromagnetic coil is electrically connected to the second moving contact through a conductor, and the other end of the electromagnetic coil is electrically connected to the first electrode cable outlet port; and when a current flowing through the electromagnetic coil exceeds a preset current threshold range, electromagnetic force generated by the electromagnetic coil attracts the armature to rotate around the shaft, and the armature pushes the rotating part to rotate, so that the circuit between the first moving contact and the first fixed contact is disconnected.