(EN) A plug-in circuit breaker in the field of low-voltage apparatus, one end of an operation button (1d) of a protection electrode of the plug-in circuit breaker is inserted into a circuit breaker shell, the operation button (1d) and a first wire outlet terminal (11) and a first wire inlet terminal (110) are arranged at the two ends of the circuit breaker shell respectively, an operation mechanism (3) and a protection mechanism (4) are arranged in the middle of a protection electrode assembly cavity side by side and are positioned between the operation button (1d) and an arc extinguishing system (5) and between the first wire outlet terminal (11) and the arc extinguishing system (5) respectively; when the plug-in circuit breaker is in a closing state, the operation mechanism (3) is in a locking and fastening state, a short circuit state or an overload state occurs, the protection mechanism (4) drives the operation mechanism (3) to trip, the plug-in circuit breaker trips and the operation mechanism (3) enters a tripping state, the operation button (1d) is pulled to drive the operation mechanism (3) to recover the locking and fastening state, and the plug-in circuit breaker enters a breaking state; or the plug-in circuit breaker is enabled to enter the breaking state, and after a fault is eliminated, the operation button (1d) is pressed to drive the operation mechanism (3) to act such that the plug-in circuit breaker is enabled to enter the closing state. The plug-in circuit breaker is compact in structure and small in size.