A low-voltage circuit breaker with a residual current trip device, wherein a plurality of circuit breaker poles which are arranged in parallel and the residual current trip device are arranged in a molded insulation shell, each circuit breaker pole comprises a pair of input/output connecting terminals (10 and 11, 20 and 21, 30 and 31, and 40 and 41), an electromagnetic trip device (14 or 53) sensitive to a short-circuit current, a thermal trip device (26 or 60) sensitive to an overload current, a static contact fixed on an integrated molded case, a movable contact in closing/breaking fit with the static contact, and an arc extinguishing device, wherein the circuit breaker poles are uniformly arranged at the two sides of the residual current trip device, adjacent circuit breaker poles at each side share a composite operating mechanism which is used for controlling the on and off of two pairs of movable contacts and static contacts, and each composite operating mechanism is provided with a handle, a rotation plate provided with a contact connection mechanism for two movable contacts of the two adjacent circuit breaker poles driven by the rotation plate, a trip connection rod pivotally arranged on the rotation plate and a trip rod; the residual current trip device comprises a residual current monitoring element, an electromagnetic relay, an auxiliary trip mechanism with an auxiliary handle, a rotation connection rod mechanically coupled with each composite operating mechanism and a test loop; a linkage element is in mutual mechanical connection and linkage with the auxiliary handle of the auxiliary trip mechanism of the residual current trip device and the handle of each of the composite operating mechanisms at two sides; characterized in that the circuit breaker further comprises a driving rod which is in connection and linkage with the handle of each of the composite operating mechanisms and the auxiliary handle of the auxiliary trip mechanism of the residual current trip device. the circuit breaker poles are uniformly arranged at the two sides of the residual current trip device, adjacent circuit breaker poles at each side share a composite operating mechanism which is used for controlling the on and off of two pairs of movable contacts and static contacts, and each composite operating mechanism is provided with a handle, a rotation plate provided with a contact connection mechanism for two movable contacts of the two adjacent circuit breaker poles driven by the rotation plate, a trip connection rod pivotally arranged on the rotation plate and a trip rod; the residual current trip device comprises a residual current monitoring element, an electromagnetic relay, an auxiliary trip mechanism with an auxiliary handle, a rotation connection rod mechanically coupled with each composite operating mechanism and a test loop; a linkage element is in mutual mechanical connection and linkage with the auxiliary handle of the auxiliary trip mechanism of the residual current trip device and the handle of each of the composite operating mechanisms at two sides; characterized in that the circuit breaker further comprises a driving rod which is in connection and linkage with the handle of each of the composite operating mechanisms and the auxiliary handle of the auxiliary trip mechanism of the residual current trip device.