The utility model discloses an arc fault detects circuit breaker, include: the casing, hold circuit breaker body and arc fault detection device in the casing. Arc fault detection device includes wiring board assembly and tripping device, and wiring board assembly and tripping device are arranged in the casing. There are arc fault in arc fault in the wiring board assembly detection line, wiring board assembly in detecting the circuit, and wiring board assembly control tripping device thread off and instruct. The utility model discloses an arc fault detects circuit breaker has integrated structure, and adopt inside and walk the mode that the electricity was got to the line, compact structure, the appearance is pleasing to the eye, and anti external disturbance can the reinforce.