A circuit breaker comprises a magnetic trip mechanism configured to provide a first mechanical driving force, a low voltage trip mechanism configured to provide a second mechanical driving force, a first micro switch configured to generate and output a first trip signal indicating that the circuit breaker has performed a trip operation due to the occurrence of a fault current on a circuit, a second micro switch configured to generate and output a second trip signal indicating that the circuit breaker has performed a trip operation due to the occurrence of a low voltage on the circuit, a first driving force transmission mechanism configured to transmit the first mechanical driving force from the magnetic trip mechanism to the first micro switch, and a second driving force transmission mechanism configured to transmit the second mechanical driving force from the low voltage trip mechanism to the second micro switch.