Circuit breaker comprising: - at least a first fixed contact and a first movable contact which can be switched between at least a circuit breaker closed status where the fixed and movable contacts (1, 2) are coupled to each other, and a circuit breaker tripped status where the fixed and movable contacts (1, 2) are separated from each other; - a signaling device suitable to be actuated in order to signal when the circuit breaker is in a tripped status; - a trip actuator suitable to move from an initial position to an end-stroke position when said at least first movable contact has to be switched from said circuit breaker closed status into said circuit breaker tripped status; - a tripping bar which is operatively connected to said first movable contact so as when said trip actuator moves from said initial position, said tripping bar moves from an un-tripped position towards a tripped position to trigger switching of said first movable contact from said circuit breaker closed status into said circuit breaker tripped status; wherein it further comprises a trip member movable between a rest position and an actuated position, said trip member having a single-piece shaped body which comprises a first portion suitable to interact with and be actuated by said trip actuator to move from said rest position towards said actuated position when the trip actuator moves from said initial position towards said end-stroke position, a second portion which is spaced apart from said first portion and is suitable to interact and actuate said tripping bar to move from said un-tripped position towards said tripped position, and a third portion which is spaced apart from said first and second portions (41, 42) and is suitable to interact with and actuate said signaling device, characterised in that said movable trip member comprises a first part on which there are provided said first and second portions (41, 42), and a second part on which there is provided said third portion, the shaped body of said movable trip member being structured so that said first part and said second part move in opposite rotation directions with respect to each other. - at least a first fixed contact and a first movable contact which can be switched between at least a circuit breaker closed status where the fixed and movable contacts (1, 2) are coupled to each other, and a circuit breaker tripped status where the fixed and movable contacts (1, 2) are separated from each other; - a signaling device suitable to be actuated in order to signal when the circuit breaker is in a tripped status; - a trip actuator suitable to move from an initial position to an end-stroke position when said at least first movable contact has to be switched from said circuit breaker closed status into said circuit breaker tripped status; - a tripping bar which is operatively connected to said first movable contact so as when said trip actuator moves from said initial position, said tripping bar moves from an un-tripped position towards a tripped position to trigger switching of said first movable contact from said circuit breaker closed status into said circuit breaker tripped status; wherein it further comprises a trip member movable between a rest position and an actuated position, said trip member having a single-piece shaped body which comprises a first portion suitable to interact with and be actuated by said trip actuator to move from said rest position towards said actuated position when the trip actuator moves from said initial position towards said end-stroke position, a second portion which is spaced apart from said first portion and is suitable to interact and actuate said tripping bar to move from said un-tripped position towards said tripped position, and a third portion which is spaced apart from said first and second portions (41, 42) and is suitable to interact with and actuate said signaling device, characterised in that said movable trip member comprises a first part on which there are provided said first and second portions (41, 42), and a second part on which there is provided said third portion, the shaped body of said movable trip member being structured so that said first part and said second part move in opposite rotation directions with respect to each other.