An air circuit breaker is disclosed. An air circuit breaker according to one aspect of the present disclosure includes a cradle and a circuit breaker main body drawn-in and drawn-out to/from the cradle; and further includes: an interlock lever connected to an off button of the circuit breaker main body to move vertically; and a transfer device unit provided on the lower side of the cradle, wherein the transfer device unit can include a key interlock assembly, which is provided to be horizontally movable so that, in a state of having moved toward one side thereof, the movement of the interlock lever is restricted and, in a state of having moved toward the other side thereof, the movement of the interlock lever is permitted.

An air circuit breaker is disclosed. An air circuit breaker according to one aspect of the present disclosure includes a cradle and a circuit breaker main body drawn-in and drawn-out to/from the cradle; and further includes: an interlock lever connected to an off button of the circuit breaker main body to move vertically; and a transfer device unit provided on the lower side of the cradle, wherein the transfer device unit can include a key interlock assembly, which is provided to be horizontally movable so that, in a state of having moved toward one side thereof, the movement of the interlock lever is restricted and, in a state of having moved toward the other side thereof, the movement of the interlock lever is permitted.